Nirukta · निरुक्त

The siddhantas each devote a chapter to spherics — the Golādhyāya — and the armillary sphere is the gola-yantra. Three compounds of gola divide the universe between them: bhūgola, khagola, bhagola.

In the Aryabhatiya's Golapada, the khagola is the sphere built from what you stand under: horizon, meridian, prime vertical. It is the fixed outer frame. Modern Hindi khagol-śāstra = astronomy.

kha is a wonderful word on its own: sky, space, cavity, aperture — and zero. Aryabhata uses kha for the empty place in his number system, and Bhāskara II calls a quantity divided by zero khahara — “the kha-divided,” his name for the infinite. The same little word sits inside sukha and duḥkha — by the cherished old gloss, a good or bad axle-hole, a smooth or jolting ride through life (traditional gloss). And a bird — or a planet — is khaga, “sky-goer.”

The inner sphere that actually turns: Aryabhata has the bhagola rotate inside a fixed khagola, and in the gola-yantra the star-sphere is mounted loose on the polar axis so it can spin while the sky-frame stands still. bha = nakshatra, “a shining one,” from √bhā “to shine, appear” — the root of bhānu (sun), prabhā (radiance), vibhāvarī (the starlit night), ābhā (luster).

From bha: bhagaṇa, “the troop of asterisms,” and therefore one full revolution through them — the siddhantas count planetary revolutions per yuga as bhagaṇas; and bhacakra, the “wheel of asterisms,” the zodiac itself.

Modern Hindi bhūgol = geography. So every Indian schoolchild studies two siddhantic spheres by name — bhūgol and khagol — while the third, the bhagola, stayed behind as the astronomers' word. That the word for geography is literally “earth-ball” is also a quiet daily reminder of what the siddhantas took for granted: the earth is a gola.

From jyotis, light — the Vedanga Jyotisha is “the limb of the Veda concerning the lights.” Astronomy and astrology were one discipline under this name; the split is modern.

The horizon is the circle where the sky is born out of the earth: kṣiti-ja, “earth-born.” It is the khagola's base circle, and the reference for every rising (udaya) and setting (asta).

The Sūrya-siddhānta (12.43) uses it for a small proof of a round earth: there are two pole-stars, one on either side of Meru, and “for those in the land without latitude, both rest on the horizon.” Āryabhaṭa's kṣitijyā, the “earth-sine” (Golapāda 26), is the piece of the day-circle below the horizon — the quantity that makes summer days long and winter days short.

Terrestrial latitude in Sanskrit is akṣa, the axle — most naturally read as the tilt of the sky's turning axle above your horizon, which is exactly what latitude is: the pole stands as high as you are far from the equator. The equator itself is nirakṣa, “axle-less” — the land where the pole lies flat on the horizon. Akṣajyā is the sine of latitude.

Its partner is lamba or lambaka, “the hanging one” — the plumb line. Āryabhaṭa uses the word both ways: “down and up, by the plumb line alone” in his surveying rules (Gaṇitapāda 13), and lambaka for the cosine of latitude in his spherics (Golapāda 26, 30). The plumb points at the zenith, and the zenith's distance from the pole is the co-latitude — so the builder's string became the astronomer's angle.

One tiny root generates the sun's yearly journey (uttarāyaṇa, dakṣiṇāyana), the two zodiacs (sāyana, nirayana), the precession correction (ayanāṃśa), an epic (Rāmāyaṇa), and a name of God (Nārāyaṇa).

The sun's two half-year courses along the horizon, turning at the solstices. This is the plainest, most physical ayana: watch sunrise from one spot for a year and you see the going with your own eyes.

Note the retroflex ṇ: the r earlier in the compound bends ayana into -ayaṇa — the same sandhi that shapes Rāmāyaṇa.

The accumulating angular gap (currently about 24°) between the tropical and sidereal zodiacs. The name is exact: it is the share of the circle that the equinox's own slow going has claimed.

The two reference frames of the entire tropical-vs-sidereal debate, compressed into two prefixes: sāyana reckoning moves with the drifting equinox (Western/tropical); nirayana subtracts the drift and stays pinned to the stars (Vedic/sidereal). A 1,500-year argument, named in four syllables each.

The day poised evenly between the two ayanas, when day and night weigh the same. The vernal viṣuva point is precisely what the ayanāṃśa measures the drift of.

Not “the story” and not “the battle”: the epic is named, like the solstices, for a going — Ayodhya to Lanka and back. The sun's uttarāyaṇa and Rāma's ayaṇa are grammatically the same kind of word.

Manusmriti 1.10 gives the classical derivation: the waters are called nārāḥ; they were his first ayana — resting place — hence Nārāyaṇa, the god who sleeps on the cosmic ocean between the ages. Here ayana's second meaning, “abode,” carries the name; an alternative reading takes it as “the ayana (refuge/path) of humans (nara).” Either way it is the same word as in uttarāyaṇa.

The devotional habit of calling the sun Sūrya-Nārāyaṇa makes a lovely closed circle: the deity of the cosmic rest, named for the sun whose ayana structures the year — a resonance, not an etymology (coincidence).

Hence dharma-parāyaṇa, “one whose ultimate course is dharma.” The going, moralized.

The Upaniṣads give the dead two roads, and both are drawn on the sky. The fathers' road ends at the Moon — “king Soma, the food of the gods” (Chāndogya 5.10.4–5) — and returns; the gods' road goes to the Sun and does not. The Gītā (8.24–25) ties them to the sun's two half-years: fire, day, the bright fortnight and the six months of uttarāyaṇa for one road; smoke, night, the dark fortnight and dakṣiṇāyana for the other.

The Purāṇas then pin the fathers' road to actual stars: “north of Agastya and south of the Goat-lane (Ajavīthī) — that indeed is the path of the fathers” (Vāyu-purāṇa 50.208). Canopus, the deepest-southern star the tradition watched, becomes a boundary mark for the road of the dead.

One root gives both: a graha is that which grips — originally the ominous seizers of sun and moon, later the nine influences that grip a life — and a grahaṇa is the act of seizing itself, an eclipse.

The eclipse's phases keep the drama: first contact is sparśa (“the touch”) and the end is mokṣa (“the release, liberation”) — every eclipse, linguistically, ends in moksha.

The sun striding over a boundary into a new rashi — Makara Saṅkrānti is simply “the step into Capricorn.” The bare noun krānti (“the stepping-out”) became the technical term for declination, and krānti-vṛtta, the circle of the sun's stepping, is the ecliptic.

The compound still works overtime in modern Hindi: saṅkramaṇ, the same “crossing-over,” is today's everyday word for infection — transmission as a stepping-across from one body to the next.

The rashi caught in the act of rising at a given moment. The same participle gives the wedding lagna: the astrologically fixed moment to which the ceremony is attached.

A 30° heap of ecliptic, twelve heaps to the circle. Indian mathematicians used the same word for any quantity in arithmetic — your rashi is, deadpan, “your pile.”

When Mars loops backward it goes vakrī — crooked. The everyday astrological word is a precise description of the apparent loop the planet traces against the stars.

Udaya is “the up-going” — the same √i as ayana. And setting is astaṁ gacchati: the sun “goes home.” Sunset, in Sanskrit, is the sun's homecoming; a combust planet (asta) is one that has gone home to the sun's glare.

Each day belongs to the graha whose turn it is — the turn being determined by the hora sequence of planetary hours. Somavāra is the Moon's turn.

The tradition's own derivation, recorded in the jyotisha literature: clip a-horātra (“day-and-night”) at both ends and horā remains — the hour as the trimmed middle of the day. Modern scholars mostly see a loanword from Greek hōra, arriving with Hellenistic horoscopy (whence horā-śāstra) — the same Greek word that gives English hour.

Both stories may be telling the truth about different moments: a borrowed word, then a brilliant native re-etymology. Either way, Sanskrit horā, Greek hōra, and English hour are one family.

A ghaṭī is literally a pot: the sinking-bowl water clock that measures the unit gave the unit its name. A nāḍikā is a tube — the outflow clock. India's fine time units are named not for abstractions but for the apparatus on the workshop floor.

Add nimeṣa, a blink, from √miṣ “to wink”; and kṣaṇa, the instant.

From muhur, “suddenly, for a moment”: a captured instant stretched into a unit. The Vedic texts already count thirty muhūrtas to one day-and-night, so one muhūrta = 48 minutes; the brāhma-muhūrta is the night's second-to-last — roughly 96 to 48 minutes before sunrise.

The semantic journey is the best part: from a moment to the moment. In living usage muhūrta (colloquially muhurat) rarely means the unit anymore — it means the astrologically chosen instant: the wedding muhurat, the griha-pravesh muhurat, the stock exchange's Diwali muhurat trading, even the film industry's inaugural “muhurat shot.” A word that began as a measure of time became the name for time's quality — the panchang's whole purpose folded into two syllables.

Before it was a comet, dhūmaketu was Agni. The fire whose banner is its smoke appears in the funeral hymn of the Atharvaveda (18.1.30) — “smoke-bannered, bright with the kindling” — and Yāska's Nirukta (6.4) cites the same line to explain the word beside it, bhāṛjīka, “of renowned light.”

The sky borrowed the fire-god's flag for a fire where no fire should be. In the Mahābhārata's war-omens (6.3.13), “the greatly terrible Dhūmaketu stands, having attacked Puṣya” — given a nakṣatra and the rank of mahāgraha, like a planet. One word, two owners, told apart only by context.

Ulkā is a firebrand, a torch — and the falling light in the sky. The Bṛhat-saṃhitā's chapter on them (33.1–8) opens with a line of pure poetry: they are “the forms of those who fall, having enjoyed in heaven the fruit of their merit” — shooting stars as souls whose credit has run out.

Then the same chapter turns observer. It divides falling lights into five kinds — dhiṣṇyā, ulkā, aśani, vidyut, tārā — by size, length of track, colour, path and sound: three silent, tailed lights that cross the sky, and two that strike the ground with a report, one with a crackling “taṭ-taṭ.” In modern Hindi ulkā is still the meteor, and ulkāpiṇḍa the meteorite.

The most transparently astronomical name in the set: Saturn takes 29½ years to crawl once around the zodiac, by far the slowest of the visible planets, and its name says exactly that. Śanivāra and Saturday are independently both “Saturn's day.”

Bṛhaspati is the gods' own priest; as Guru, “the heavy one,” he is the teacher — weight as gravitas. Guru is cognate with Latin gravis and Greek barys: guru ~ gravity.

That Jupiter is in fact the most massive planet in the solar system is a delicious accident — the ancients named his dignity, not his mass.

The same root as Buddha. Mercury, the intelligence among the grahas, is also the planet visible only at waking hours — dawn and dusk — a poetic fit the name may or may not intend.

Accurately named: Venus is the brightest planet. The same root gives śukla, “bright” — so Śukra the planet and the śukla pakṣa (bright fortnight) are siblings.

Aṅgāraka — “like a glowing coal” — names what the eye sees: the red planet. Maṅgala, “the auspicious,” is the opposite of what the fierce planet was feared to be: a protective euphemism, the same politeness that calls smallpox's goddess Śītalā, “the cool one.” Also Bhauma / Kuja, “son of the Earth.”

Sūrya belongs to the oldest layer of the language — cognate with Latin sōl, Greek hēlios, English sun. Candra, “the glittering,” shares an ancestor with Latin candēre “to glow white” — so candra ~ candle, incandescent, candid.

Soma is “the pressed juice” of the ritual — the moon as the gods' cup of amṛta, drained dark and refilled through the month: the waxing-waning story that the Somnath legend retells as Chandra's curse and cure.

Rāhu, most likely from √rabh, is the grasper who swallows sun and moon — mythic shorthand for the eclipse-producing lunar node. Ketu is “banner, bright apparition”: the comet's tail, the streamer — and, as the descending node, the severed remainder of the seizer.

Between them the two “shadow planets” encode real geometry: eclipses happen only where the two rings cross.

From kuṇḍala, ring, coil, earring — the family of kuṇḍa, the round vessel (the havan-kund's word). The chart is named for the circle it once was: the ecliptic ring drawn flat. North India draws it as a diamond and the South as a grid, but the name remembers the original shape — the sky's circle, frozen at the moment of a birth.

A janma-kuṇḍalī is “the ring of one's birth.” Same coiled family: kuṇḍalinī, the serpent said to lie coiled at the spine's base.

Already a Rigvedic word for ram, with an Avestan cousin (maēša). Greek Krios, Latin Aries: every tradition sees a ram here; Sanskrit simply supplied its own oldest word for one.

The bull as the fertilizing rainer — the same root gives varṣā, the rains, and varṣa, the year the rains measure out. Taurus, the monsoon, and the Sanskrit word for “year” are one family: in India, even the bull rains.

Where Greek says “twins” (Didymoi), Sanskrit says “the coupled two” — the same mithuna as the amorous couples on temple walls. A translation with its own warmth.

The star cognate row of the whole wheel: Sanskrit karkaṭa, Greek karkinos, Latin cancer share an ancient hard-shell word. Greek karkinos is also the source of carcinoma — so the rashi and the disease are cognates, both named for the crab.

The word's own past is murky, but its descendants are famous: Singh, Sinhala (“the lion people”), and Siṃhapura — Singapore. Every Singh carries a rashi name.

Greek Parthenos, Sanskrit “the young girl, the daughter.” Kanyakumari, the cape of the virgin goddess at India's southern tip, carries the same word.

From √tul come tulya “equal” and tulanā “comparison” — and the root's wider Indo-European career: Greek talanton, a weight (whence talent), Latin tollere/tolerāre, to lift, to bear (whence tolerate). To weigh, to be equal, to have talent, to bear patiently: the scales-sign carries the whole cluster.

Named by its verb — for what the sting does.

Greek names the archer (Toxotēs); Sanskrit names the weapon — the constellation reduced to its defining object. Its science is dhanurveda, archery.

For the Greco-Babylonian goat-fish, Sanskrit reached for its own native water-beast: crocodile-snouted, fish-tailed, Ganga's mount, Kamadeva's emblem. Its vernacular descendant magar gave English the mugger crocodile.

And Makara Saṅkrānti — the January kite day — is, literally, “the step into the sea-beast.”

Greek has a water-pourer (Hydrokhoos); Sanskrit keeps just his pitcher. India's pot-affections run deep: the ghaṭī time-pot, Kumbhakarna “pot-ears” — and the Kumbh Mela, named for the spilled pot of amṛta and timed by Guru's transits, so that the festival's name and the rashi's name are the same pot.

Most scholars take mīna as an old borrowing from Dravidian — where Tamil mīṉ means both fish and star (viṇmīṉ, “sky-fish,” is a star). If so, the twelfth rashi carries a gift from India's other great language family, in which the fish already swam in the sky. Meenakshi, “the fish-eyed goddess,” shares it.

The name's root is uncertain — “the cutters” is the usual guess, perhaps for Agni's blades of flame. Their god is Agni, and the Śatapatha-brāhmaṇa (2.1.2.1–3) gives three reasons to set up the sacred fires under them: they are Agni's own asterism; they have the most stars, where the others have “one, two, three or four”; and “they do not swerve from the eastern quarter,” while all the others do.

That last line — the Pleiades rising due east — has been used since Dikshit (1895) to date the text: it was exactly true when they sat on the celestial equator, in the third millennium BCE. Whether the observation was that precise is still argued. The next verse adds a love story: the Kṛttikās were once the wives of the Ṛkṣas, the Bears, who are now the Seven Sages — kept apart forever, since the Sages rise in the north and the Kṛttikās in the east. They gave their name to the month Kārttika and to Kārttikeya, the god they nursed.

Rohiṇī is “the red one,” and Aldebaran is the orange-red eye of the Bull — one of the few naked-eye star colours the name actually records. The Aitareya-brāhmaṇa (3.33) tells the story outright: Prajāpati chases his daughter, “and the red doe (rohit) — she is Rohiṇī.”

She is the Moon's favourite wife among the twenty-seven, and the star of Kṛṣṇa's birth. The V of the Hyades is her “cart” (śakaṭa), and a planet passing through it — the Rohiṇī-śakaṭa-bheda — was one of the gravest omens in the Bṛhat-saṃhitā.

One sentence of the Aitareya-brāhmaṇa (3.33) puts four names in the sky at once. Prajāpati, pursuing the red doe, is pierced by an arrow and flies upward: “him they call the Deer; the Deer-hunter is just he; the red doe, she is Rohiṇī; the three-jointed arrow is just the three-jointed arrow.” The Deer is Orion (the nakṣatra Mṛgaśiras is its head), the arrow most likely the three stars of the Belt, the hunter Sirius.

The hunter kept his name into the siddhāntas: the Sūrya-siddhānta's star-catalogue (8.10) puts “Mṛgavyādha at the twentieth degree of Gemini” in the same verse as Agastya — the sky's two brightest stars catalogued in one breath. The modern identifications are strong but not certain; the text names, it does not point.

The Śatapatha-brāhmaṇa (2.1.2.11) lets out a secret. The Phalgunīs are Indra's nakṣatra and are named after him: “Indra is by name Arjuna — that is his secret name — and these are by name the Arjunīs. They call them indirectly ‘Phalgunīs,’ for who may take his secret name?” The Ṛgveda's wedding hymn (10.85.13) still uses the older name, arjunī.

The epic remembers both halves. Arjuna, the son of Indra, carries his father's secret name, and among his ten names is Phalguna — said to be for his birth under Uttara Phalgunī. The month Phālguna is named from the same stars.

Abhijit, “the victorious,” is the nakṣatra that was dropped. The older lists count twenty-eight; the computing tradition settled on twenty-seven equal parts of 13°20′ — and Abhijit survived as a sliver squeezed between them. Vaṭeśvara (904 CE, 2.6.6) gives it twice: as what is left of the circle after twenty-seven lunar days' motion, and as a place — the last quarter of Uttarāṣāḍhā plus the first four ghaṭīs of Śravaṇa, about 4°14′. Almanacs still use exactly that window.

It also lives on as a time of day. The Abhijit muhūrta is the one around local noon — and the Bhāgavata (8.18.5–6) has Vāmana born “at the muhūrta Abhijit, the sun gone to midday.” A star that lost its seat in the circle kept the brightest hour of the day.

The seven bright stars of the Great Bear are the Seven Sages, named star by star in the Bṛhat-saṃhitā (13.5–6) from Marīci at the east end, then Vasiṣṭha — “and there the virtuous Arundhatī keeps close to the sage Vasiṣṭha.” That is Alcor beside Mizar, a famous naked-eye eye-test: Caraka (Indriya-sthāna 11.5) says whoever cannot see Arundhatī near the Seven Sages sees “thick darkness” within a year. At weddings the bride is still shown Arundhatī, the faithful wife.

And the Bear is older than the Sages. The Śatapatha-brāhmaṇa (2.1.2.4) says “the Seven Sages were formerly called the Ṛkṣas” — and ṛkṣa, “bear,” is the same word as Greek arktos and Latin ursus. Whether India and Greece each kept an ancient “bear” in this corner of the sky, or ṛkṣa (bear) was merely confused with ṛṣi (sage), has been argued since Max Müller. The Purāṇas give the group its own clock: a Saptarṣi year of 3030 human years (Brahmāṇḍa 1.29.17), and the Bṛhat-saṃhitā has them stay a hundred years in each nakṣatra.

The tradition's own etymology is a story: Agastya is “he who stopped the mountain” — aga, “the one that does not go,” is a mountain — for the sage who made the Vindhya bow down and never let it rise again. It is a lovely gloss and probably not history, but it fits a sky built on verbs of motion.

The star is Canopus, the second-brightest in the sky and the deepest-southern one the tradition followed: the Sūrya-siddhānta (8.10) puts it eighty degrees south. Its first appearance before dawn, in early autumn, marked the end of the rains — “at the rising of Agastya the waters, fouled with mud, become clear again, like the hearts of the good” (Bṛhat-saṃhitā 12.7).

The arc of a circle is a bow (cāpa, dhanus); the chord that spans it is the bowstring, jyā or jīvā. Indian astronomers worked with the half-chord, ardha-jyā, which is the modern sine, and shortened it back to plain jyā. Āryabhaṭa uses both words in a single verse (Golapāda 30): the “jīvā of the greatest declination” and the “desired jyā.”

Then the word travelled. Arabic astronomers took jīvā over as jība; Arabic script usually leaves out short vowels, so it was written jb — and later readers took it for jayb, “pocket, fold of a garment.” Twelfth-century Latin translators (Gerard of Cremona is usually named) put jayb into Latin as sinus, “fold, bay” — and so every “sine” in the world is a translated misreading of a Sanskrit bowstring. “Cosine” is complementi sinus, the koṭijyā of the Indian tables.

If the arc is the bow and the chord its string, the line from the string's middle to the bow's belly is the arrow nocked in it: śara (also bāṇa, iṣu), the versine — the height of a circle's segment. Archery all the way down: arc, string, arrow.

Bhāskara II and the later handbooks also use śara and bāṇa for a planet's latitude — how far it is “shot” off the ecliptic. And in the word-numeral system śara means five, for the five arrows of Kāma.

A right triangle in Sanskrit has an arm (bhuja, bāhu, doḥ), an upright (koṭi) and a hypotenuse, karṇa — “the ear.” Laid on a circle, the bhuja's sine (dorjyā) is the sine, and the koṭi's sine (koṭijyā) is the cosine. Bhāskara I (Laghubhāskarīya 2.1–2) defines them for a planet's anomaly: in each quadrant “the bhuja and koṭi are the elapsed and the to-come.”

Koṭi's first meaning is the curved tip of a bow — the archery again — and from “tip, highest point” it also became a number: ten million, the koṭi that every Indian knows as a crore.

One of a small family of Greek words that came with Hellenistic horoscopy and stayed. In astronomy kendra is the anomaly: “the mean less the apogee is the kendra” (Laghubhāskarīya 2.1). In the horoscope the kendras are the four angles — houses 1, 4, 7 and 10 — just as the Greek kentra were.

Its relatives are easy to spot once you know to look: āpoklima (apoklima), paṇaphara (epanaphora), jāmitra (diametron, the opposite house), drekkāṇa (dekanos), liptā (lepta) and horā (hōra). Modern Hindi kendra is any centre — the same word that once meant only the angles of a birth chart.

The arc-minute has two names, one borrowed and one home-grown. Liptā is Greek lepta, the astronomers' “small parts”; kalā is native Sanskrit for a small portion, first of all a sixteenth of the Moon's disc. Seconds are vikalā or viliptā.

The Sūrya-siddhānta (2.64) builds the panchang on liptās: “the portion of an asterism is eight hundred minutes; of a tithi, seven hundred and twenty.” It never says twenty-seven or thirty — the counts drop out of 21,600 minutes divided by 800 and by 720. Bhāskara II adds the geometer's footnote: “in a small circle the minutes are small, in a large one large.”

A planet's true place takes two corrections, named simply by speed: manda, “slow,” and śīghra, “quick.” Āryabhaṭa gives each its own epicycle (Gītikā 10). The manda correction is the equation of centre; the śīghra correction — in modern terms the Earth's own motion seen from the planet — is the one that makes planets loop backwards and go vakra.

The point where a planet moves slowest is its ucca, “the high,” the mandocca or apogee; the opposite is nīca, “the low.” Uccha and nīca survive in astrology as a planet's exaltation and debilitation — words that began as a geometry of distances.

Every computation starts with the madhyama — “middle,” the mean planet moving evenly — and ends with the sphuṭa, the true place, “burst open” into view: what the eye actually sees. Brahmagupta put the word in his title: the Brāhmasphuṭa-siddhānta is the Treatise of Brahmā, Corrected.

The verb still means coming into the open: sphuṭ-ana is splitting, and a sphuṭa statement is a clear one. The mean is what the arithmetic predicts; the true is what bursts out of it.

Two distances, both described as motions. Declination is apakrama, the “stepping-away” from the equator (krānti, from the same root as saṅkrānti); Āryabhaṭa's “greatest apakrama” is the 24° tilt of the ecliptic. Latitude is vikṣepa, “throwing apart” — how far a planet or star is flung off the ecliptic.

The Sūrya-siddhānta's star catalogue lists the vikṣepas of the junction-stars in word-numerals (8.6): “in the north diś, māsa, viṣaya” — 10, 12, 5 — “in the south pañca, diś, nava” — 5, 10, 9. That last nine degrees south is the number on which the identity of Ārdrā's star hangs.

Gaṇa is a troop and a count — the root of gaṇita, “that which is counted,” and of Gaṇeśa, lord of the troops. A bhagaṇa is one full circuit of the stars, and the revolution-counts in a yuga are the base constants of the whole science: Āryabhaṭa's Sun makes 4,320,000 in a yuga, his Moon 57,753,336, and — the boldest clause in the Āryabhaṭīya (Gītikā 3) — the Earth turns 1,582,237,500 times “eastward.”

The ahargaṇa is the heap of days: civil days counted from an epoch. Multiply it by the revolutions and divide by the days in a yuga (Bhāskara I's 1,577,917,500), and out comes every mean planet. It is the same idea as the astronomers' Julian Day — and still how the Rashtriya Panchang counts the Kali day.

Śūnya, the empty, is zero — and its synonym is the sky. A ninth-century commentator spells it out: “the word kha is a synonym for sky; the meaning is zero” (Laghubhāskarīya-vivaraṇa on 2.2–3). Arabic translated śūnya as ṣifr, “empty”; medieval Latin made that zephirum and cifra — whence both zero and cipher.

To fit numbers into verse, astronomers wrote them as things: kha or ambara (sky) for 0, Moon for 1, the twin Aśvins for 2, Veda for 4, arrows for 5, mountains for 7 — read from the right, units first. So the Sūrya-siddhānta's (2.64) kha-aśvi-śaila, “sky-twins-mountains,” is 0-2-7, the number 720. The same verse in plain figures would not scan; in words it is poetry that computes.

The oldest instrument is a stick in the ground: śaṅku, the peg, standardly twelve finger-breadths tall. Its chāyā, the shadow, gives east and west, the time of day, the solstice, and — from the noon shadow at the equinox — the latitude.

Before the gnomon there were stars: a commentary on the Āpastamba-śulbasūtra (1.2) lists ways of finding east for an altar — sight the Kṛttikās, or Śroṇā, or the midpoint between Citrā and Svāti — and only then the stick-and-circle method. And Varāhamihira (Bṛhat-saṃhitā 3.1–3) uses the same shadows to prove the solstices had moved since the old texts: “there certainly was a time” when they were elsewhere — precession, verified by observation.

Time as that which impels all things forward — and also counts them. Kāla is simultaneously Death, and Śiva as Mahākāla, “Great Time,” has his seat at Ujjain — the very city through which the siddhantas run their prime meridian. India's Greenwich is, by name, the temple of Time itself.

The calendar imagined as a body with five limbs: tithi (the lunar day), vāra (the weekday-turn), nakṣatra (the moon's station), yoga, and karaṇa. yoga here is √yuj yet again — the “joining,” the sum of the sun's and moon's longitudes, a third astronomical career for the yoke-root after yuga and yoga-the-discipline; and karaṇa is “the doing, the instrument” (√kṛ, the root of karma), the half-tithi that is the panchang's working sub-unit.

aṅga, limb, is the same word as in Vedāṅga: jyotiṣa is one of the six “limbs of the Veda,” traditionally honored as its eye. And pañca, five, has famous cousins: Greek pente (pentagon), English five — and, by the usual account, the drink punch, carried into English from Hindi pāñc for its five ingredients. The almanac, the pentagon, and the punch bowl share a number.

The single best etymology in the calendar. Sanskrit mās is both “moon” and “month,” from √mā, “to measure”: the moon is literally the measurer, the first instrument of timekeeping, and the month is one measuring.

The whole family agrees: Greek mēn, Latin mensis, English moon and month — one prehistoric word, one prehistoric insight.

Ṛtu and ṛta — the Vedic word for cosmic order — are the same family: the seasons are the visible portion of the universe's orderliness.

Linguists connect Latin rītus (whence ritual) and Greek harmonia to the same “fitting-together” root (debated). Season, order, rite: one cluster.

Before yuga meant a world-age of hundreds of millennia, it meant the Vedanga Jyotisha's five-year intercalation cycle: the period that yokes the lunar and solar years back into step. A yuga is what harnesses the two clocks that never quite fit — the moon's and the sun's.

Yuga, yoga, Latin iugum, English yoke — all one word.

The month as a bird with two wings: śukla (bright) and kṛṣṇa (dark). The same word gives “side” in an argument — pakṣa and vipakṣa.

Astronomically perfect: on amāvāsyā the sun and moon dwell in the same house — conjunction, 0° elongation. The tithi's name is its definition.

Its opposite, pūrṇimā, is simply “the full one” — pūrṇa, from √pṝ “to fill,” cognate with Latin plēnus and English full itself.

An honesty entry: for one of the most-used words in the calendar, no derivation has convinced everyone — the tradition itself offers several. A good reminder that some of the oldest working words have outlived their own etymologies.

Hidden inside is vatsa, “calf” — a yearling, the animal that measures a year of the herd. Cognates: Greek etos “year,” Latin vetus “old (in years)” — so saṃvatsara and veteran share an ancestor. The saṁvat of “Vikram Samvat” is its clipped form.

Yāska's Nirukta derives it from nakṣ, “to reach, approach” — the stations the moon reaches night by night, which fits the system's function precisely. The Brāhmaṇa literature tells a folk story from na-kṣatra, “no dominion” — the stars stripped of power (traditional gloss). And the resemblance to nakta “night” (cognate with Latin nox, English night) has tempted many, though it remains speculative.

Three stories, one word, twenty-seven stations.

Vedic stṛ́ is Sanskrit's direct share of the great Indo-European star-word: Greek astēr, Latin stella, Persian sitāra (whence Hindi sitārā), English star. Classical tārā is its close relative, and the tradition hears √tṝ, “to cross, to ferry over,” in it — Tārā the goddess “who ferries across,” the stars as crossers of the night sea (traditional gloss).

And dhruva, the pole star, is “the firm one” — from √dhṛ, “to hold fast”: the same root as dharma, that which holds. The fixed star and the moral order share a verb.

The smallest everyday units of time are things a body does. A nimeṣa is a blink, and the Brahmāṇḍa-purāṇa (1.29.5) sets it equal to one short syllable; the gods, who never blink, are animeṣa. A prāṇa is one breath — ten long syllables, about four seconds — and the Sūrya-siddhānta (1.10–11) makes it the threshold of real time: time from the breath upward is mūrta, “embodied,” measurable; the tiny units below it are amūrta, only arithmetic.

Āryabhaṭa adds the beautiful part (Gītikā 6, Kālakriyā 2): “in one prāṇa the sky turns one minute of arc.” A sidereal day is 21,600 breaths, and the circle is 21,600 minutes — the breath and the sky keep the same count.

Sandhyā is the joint where night and day are put together — dawn and dusk — and the rite said there. The Taittirīya-āraṇyaka (2.2) gives its reason: demons fight the sun as he rises, so “facing east at the sandhyā” the brahmins throw up water charmed with the Gāyatrī, and it becomes a thunderbolt. Manu (2.101) sets the clock: stand at dawn until the sun is seen; sit at dusk until the stars appear.

The same word joins ages: every yuga has its twilight, a sandhyā before and a sandhyāṃśa after. Brahmagupta (1.10) builds his kalpa out of exactly such junctions between the Manus. From a few minutes of dusk to thousands of years — the joint is the same idea.

The lunar and solar years never fit, so every two and a half years or so the calendar gets an extra month. The Arthaśāstra (2.20.65–66) already states it as a rate: sun and moon each lose a day's piece every season, and together they make an intercalary month “the first in summer, the second at the end of five years.”

The later rule is wonderfully clean (Muhūrtacintāmaṇi 3.20): a lunar month that holds no solar ingress — no saṅkrānti — is adhimāsa, the extra month; one that holds two is kṣayamāsa, the lost month. Popularly the extra month is malamāsa, the “impure” month, unfit for weddings — and, by devotional reversal, Puruṣottama-māsa, sacred to Viṣṇu.

A parvan is the knot on a bamboo cane, the joint of a limb. The month has joints too: the new moon and full moon, the points where it bends from one fortnight to the next, are the parvans — the classic days for sacrifice, for eclipses, and for not doing ordinary work.

From joint to occasion: Hindi parv is any festival, and the Mahābhārata's eighteen books are parvans, the sections where the cane of the story is jointed. The Brahmāṇḍa-purāṇa (1.21.133) counts the parvans of a five-year yuga as carefully as its sunrises.

Kalpa means an arrangement, an ordinance — the Kalpa-sūtras are ritual manuals — and then the greatest arranged span of time: one day of Brahmā, a thousand caturyugas, 4.32 billion years. Even this has variants: Brahmagupta (1.10–12) builds his kalpa of a thousand yugas with twilight junctions, and notes that Āryabhaṭa's has a thousand and eight.

Parārdha, the “far half,” began as a number: the top of the Yajurveda's ladder of powers of ten (Vājasaneyi-saṃhitā 17.2), 10¹², recited over the altar bricks “may these be milk-cows for me.” Later it names half the life of Brahmā. A word for the end of counting became a word for the end of time.