SB 3.11.10
Devanāgarī
यामाश्चत्वारश्चत्वारो मर्त्यानामहनी उभे । पक्ष: पञ्चदशाहानि शुक्ल: कृष्णश्च मानद ॥ १० ॥
Text
yāmāś catvāraś catvāro martyānām ahanī ubhe pakṣaḥ pañca-daśāhāni śuklaḥ kṛṣṇaś ca mānada
Synonyms
yāmāḥ—three hours;catvāraḥ—four;catvāraḥ—and four;martyānām—of the human beings;ahanī—duration of day;ubhe—both day and night;pakṣaḥ—fortnight;pañca-daśa—fifteen;ahāni—days;śuklaḥ—white;kṛṣṇaḥ—black;ca—also;mānada—measured.
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.