Fortnight or a lunar phase in a month of the Hindu lunar calendar
Paksha (Sanskrit: पक्ष, romanized: pakṣa) refers to a fortnight or a lunar phase in a month of the Hindu lunar calendar. Literally meaning "side", a paksha is the period either side of the purnima (full moon day). A lunar month in the Hindu calendar has two fortnights, and begins with the purnima (new moon). The lunar days are called tithis; each month has 30 tithis, which may vary from 20 – 27 hours. A paksha has 15 tithis, which are calculated by a 12 degree motion of the moon.
https://en.wikipedia.org/wiki/Paksha