1788, "to spray with urine" (trans.), euphemistic abbreviation of piss. Meaning "to urinate" is from 1879. Related: Peed; peeing. Noun meaning "act of urination" is attested by 1902; as "urine" by 1961. Reduplicated form pee-pee is attested by 1923.

1893, American English, in the figurative sense "fear or doubt that reverses an intention to do something;" the presumed Italian original (avegh minga frecc i pee) is a Lombard proverb meaning "to have no money," but some of the earliest English usages refer to gamblers, so a connection is possible.

"heavy coat generally worn by sailors in cold or stormy weather," 1721, a partial loan-translation of North Frisian pijekkat, from Dutch pijjekker, from pij "coarse woolen cloth" + jekker "jacket." Middle English had pee "coat of coarse, thick wool" (late 15c.). Related: Pea-coat.