Śrīmad-Bhāgavatam 3.11.10
SB 3.11.10
Open the full passageSanskrit
yāmāś catvāraś catvāro martyānām ahanī ubhe pakṣaḥ pañca-daśāhāni śuklaḥ kṛṣṇaś ca mānada
Translation
It is calculated that there are four praharas, which are also called yāmas, in the day and four in the night of the human being. Similarly, fifteen days and nights are a fortnight, and there are two fortnights, white and black, in a month.