刹那

(sa) kṣaṇa. An indefinite space of time, a moment, an instant; the shortest measure of time, as (sa) kalpa is the longest; it is defined as 一念 a thought; but according to another definition 60 (sa) kṣaṇa equal one finger-snap, 90 a thought 念, 4,500 a minute; there are other definitions. In each (sa) kṣaṇa 900 persons are born and die.