सिद्धान्तशिरोमणि: गणिताध्याय (भास्कराचार्य - ग्रहगणित, मध्यमाधिकार व स्पष्टाधिकार सटीक)

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89. Tithi-kṣaya : Since a Tithi falls short of a Sāvanāha
or civil day, in course of time, it so
happens, that a tithi begins after sun-rise
and does not last upto the next sun-rise.
Such a tithi is said to be lost and goes
by the name Tithi kṣaya. One such tithi
kṣaya occurs out of 64 tithis approximately
or eleven out of 703 more approximately.
90. Tretāyuga : Thrice the period of a Kaliyuga.
91. Trijyā : The Hindu sine of three Rasis or 90°
equal to R or 3438 units.
92. Udaya : Rising or heliacal rising.
93. Unmaṇḍala or : The great circle through the celestial pole
Udvṛtta and the east point.
94. Unmaṇḍala : The Hindu cosine of the altitude of a
Śaṅku celestial body situated on the unmaṇḍala.
95. Upavṛtta : A small circle parallel to the prime vertical
through a star or a planet.
96. Vighaṭi or Vināḍi: One sixtieth of a ghaṭī.
97. Vikṣepa or śara : Celestial latitude.
or Viśikha
98. Viṣuvatbindu : Equinoctial point.
99. Viṣuvat-chāyā : The shadow cast by the gnomon when the
Sun is at the point of intersection of the
celestial equator and the meridian on an
equinoctial day.
100. Viṣuvat-Vṛtta : Celestial equator.
101. Vṛtta or Maṇḍala: A circle.

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102. Yāmyottara- : The Hindu sine of the Altitude of a
saṁku or Celestial body situated on the meridian.
Dinārdha-Śaṅku
103. Yāmyottaravṛtta : The meridian at a place.
104. Yaṣṭi : R² - Ayanavalanajā²
Yaṣṭi has also another meaning namely
the length of the perpendicular from a
point on the diurnal circle on the plane
parallel to the plane of the horizon through
the point of intersection of the diurnal
circle with the unmaṇḍala.
105. Yoga : The time which elapses when the sum of
the longitudes of the Sun and the Moon
to increase by 13¹⁄₃º starting from zero.
106. Yuti : Conjunction.