The definition of a peep is a small sound or word, or a quick look.(noun)
To peep is to make a high-pitched sound, or to look through a small space.(verb)
See peep in Webster's New World College Dictionary
Origin: ME pepen: orig. echoic
Origin: ME pepen, ? akin to piken, peek
See peep in American Heritage Dictionary 4
intransitive verb peeped, peep·ing, peeps
Origin: Middle English *pepen
Origin: , probably alteration of pipen
Origin: , from Old English pīpian, to pipe
Origin: , from pīpe, tube, musical instrument
Origin: , and from Latin pīpāre, to peep; see pipe.
verb peeped, peep·ing, peeps verb, intransitive
Origin: Middle English pepen
Origin: , perhaps alteration of piken, to peek; see peek.
Learn more about peep