Puff

A puff is one inhalation/exhalation unit — functionally interchangeable with "hit" in most self-report instruments, though some technical measurement literature treats "puff" as the term denoting an observable draw with measurable puff volume (mL), velocity, and duration (puff topography). Gray, Watson & Christie (2009) proposed quantifying cannabis use "based on number of puffs ('hits')," treating the terms as synonyms. Laboratory studies nonetheless document that puff count is an imperfect proxy for delivered THC because puff volume and breath-hold vary widely within and between users. Note — ambiguity: Some popular sources distinguish "hit" (a full/long inhalation) from "puff" (a shorter draw); peer-reviewed measurement literature (DFAQ-CU, unit-preference grids) treats them as synonymous.