A tithi () is the time taken by the moon to advance 12° with respect to the earth-sun axis.Burgess 1935, p. 104 (II. 64) In other words a tithi is the time taken for the moon's elongation (on the ecliptic plane) to increase by 12°. A tithi is one fifteenth of a pakṣa and one thirtieth of a cāndramāsa. A tithi corresponds to the concept of a lunar day.
