Shastric Lexicon
37 Sanskrit, mathematical, astronomical and architectural terms from Vedic literature, the classical treatises, and the computational implementations that follow them.
The fundamental unit of civil and sacred Vedic time, measured strictly from local apparent sunrise (Sūryodaya) to the subsequent sunrise.
The angular separation between the moving Tropical Vernal Equinox (Sayana 0° Aries) and the fixed Sidereal Zodiac (Nirayana 0° Mesha). Pūjāvāni uses the Chitrapaksha / Lahiri ayanāṃśa the Calendar Reform Committee recommended (about 24.2° in 2026).
The principle of the siddhāntic tradition that a computation is corrected until it agrees with the sky as it is observed.
A period during which the celestial longitudinal elongation of the Moon from the Sun increases by exactly 12°. There are 30 Tithis in a synodic lunar month.
One half of the synodic lunar month: Śukla Pakṣa (waxing, from New Moon to Full Moon) and Kṛṣṇa Pakṣa (waning, from Full Moon to New Moon).
The sidereal ecliptic divided into 27 equal 13°20′ arcs, each governed by a Vedic deity and characterized by fixed marker stars (Yogatārās).
One quarter of a Nakshatra arc (3°20′). A 108-pada cycle completes the 12 signs of the D9 Navamsha chart.
The 27 mathematical intervals defined by the sum of the Sun and Moon sidereal longitudes: (λ_Sun + λ_Moon) mod 360° / 13°20′.
Half of a Tithi (6° lunar elongation). There are 60 Karanas in a lunar month, comprising 7 repeating Chara (movable) and 4 Sthira (fixed) Karanas.
A Tithi that begins after sunrise and ends before the subsequent sunrise, thus not coinciding with any Suryodaya.
A Tithi that is active during two consecutive sunrises due to slower lunar orbital velocity near apogee.
The exact degree of the sidereal ecliptic intersecting the eastern horizon at a given geographical observer latitude and Local Sidereal Time.
The period of observance before an eclipse in the dharma-śāstra tradition: 12 hours (4 praharas) before a solar eclipse and 9 hours (3 praharas) before a lunar eclipse, observed only where the eclipse is visible.
The rule the reference applies: the observances attached to an eclipse or a planetary conjunction apply where it is visible above the local horizon, and not elsewhere.
The centroid of the plot polygon, calculated by the shoelace formula, from which the sixteen directional zones are measured.
The central nine padas of the 81-pada grid, one ninth of the plot, or the central four of the 64-pada grid. The texts ask that Brahmā's area be kept free of impurity and that no pillar, peg or vessel stand on a marma there.
The nine-by-nine grid on which a house is laid, holding forty-five deities. The Bṛhat Saṃhitā and the Mayamata assign its padas differently.
The eight-by-eight grid on which temples are laid, in the Bṛhat Saṃhitā and the Mayamata.
The two diagonals of the grid, Roga–Anila (north-west to south-east) and Pitṛ–Śikhī (south-west to north-east), two of the six vaṃśa lines, which cross at the centre.
The intersections of the vaṃśa lines and the centres of the padas, on which the text asks that no vessel, peg or pillar stand. The nine crossings of the lines are the atimarmas.
The systematic geometric division of a plot or floor plan into dedicated micro-cells or deity zones.
The tradition's preference for keeping the Brahmasthāna open. Modern practice extends the preference to the north-east; that extension is practice, not a located verse.
A measure in hastas multiplied by 8 and reduced mod 12. What is measured differs by tradition: the length in the Mānasāra, the half-perimeter in the Mayamata, the area in the engine's default reading.
A measure in hastas multiplied by 9 and reduced mod 10. The rule the traditions share is that the āya should exceed the vyaya.
A measure in hastas multiplied by 3 and reduced mod 8 gives one of eight animals, each with a direction. The odd ones (Dhvaja, Siṃha, Vṛṣa, Gaja) are the good ones and the even ones are not.
The circumference multiplied by 9 and reduced mod 7 in the Mānasāra, which counts Friday, Thursday, Monday and Wednesday good. The Mayamata's rule for the vāra is located but not settled.
The engine's own test, the area in hastas × 27 mod 100. No located verse gives it; the Viśvakarma Prakāśa's āyu uses 8 over 120. It is a modern convention and predicts nothing about a building's life.
The kiṣku hasta of 24 aṅgulas, taken by the engine as 0.4572 m (18 inches). The texts name other hastas of 25 to 31 aṅgulas, and no text gives the aṅgula in metres.
Ancient Sanskrit science of tree care, soil diagnostics, organic fertilizers, and cardinal botanical placement.
Five trees: aśvattha, bilva, vaṭa, dhātrī (āmalakī) and aśoka. The five are attested; where each stands is not fixed by any primary edition located, and published layouts disagree.
A liquid manure described in the Vṛkṣāyurveda, made by fermenting animal matter, oilcake and other ingredients in water.
The texts' rules for housing and keeping cattle, and for returning their dung and urine to the land.
Celebrated author of Pañcasiddhāntikā, Bṛhat Saṃhitā, and Bṛhat Jātaka from Ujjain.
Pioneered diurnal rotation of Earth on its axis, epicyclic models, and sine tables in Āryabhaṭīya.
Author of Siddhānta Śiromaṇi; known for the cyclic method (cakravāla) for indeterminate equations and for treating instantaneous planetary velocity.
King of Dhārā, credited with the Samarāṅgaṇa Sūtradhāra and the Yuktikalpataru, which treat town planning, architecture and mechanical devices (yantras).
Formulated the Saha Ionization Equation; Chairman of the Government of India Calendar Reform Committee (1952–1955).