peter.

US, 1902, presumably from shared initial pe-. Compare the use of other men’s names as slang terms for the penis, e.g., dick, willy, johnson, John Thomas, etc.

Unknown. Attested from the 18th century. The Canting Academy defines peeter as “A portmantle”; Green’s Dictionary of Slang list a variety of uses for peter – including trunk or portmanteau – in thieves’ cant in Britain, Australia, New Zealand, and the United States. The OED suggests that it may be related to St. Peter being the holder of the keys to God's Kingdom.

Etymology tree Proto-Indo-European *sḗh₂l Proto-Italic *sāls Latin sāl Pre-Greekder.? Ancient Greek πέτρᾱ (pétrā)bor. Latin petrae Medieval Latin sāl petrae Old French salpetrebor. Middle English saltpetre English (salt)peter? Proto-Indo-European *pesd- Proto-Indo-European *-eti Proto-Indo-European *pésdeti Proto-Italic *pezdō Latin pēdō Proto-Indo-European *-tósder. Latin -ītum Latin pēditum Old French pet Middle French pet French pet Proto-Italic *-āzi ▲ Latin -ereinflu. Latin -āre Old French -ier Middle French -er French -er French péterbor.? English peter Unknown; the following etymologies have been suggested: * From peter (“to stop (doing or saying something)”) (slang, obsolete, rare). * Since the word was first used in mining contexts, either: ** from French péter (“to explode; to break wind, fart”) (slang), from pet (“emission of digestive gases from the anus, flatus, fart”) (slang), from Latin pēditum (“flatus, fart”), from pēdō (“to break wind, fart”), ultimately from Proto-Indo-European *pesd- (“to break wind softly”), probably imitative; or ** from (salt)peter, a variant of saltpetre (“potassium nitrate”) (the key ingredient in gunpowder), from Middle English salpeter, salpetre [and other forms] with the first element influenced by salt, from Old French salpetre (modern French salpêtre), from Medieval Latin salpetra, from Latin sāl petrae (literally “salt of stone”) (as potassium nitrate occurs encrusted on some stones), from sāl (“salt”) + petrae (the nominative or vocative plural of petra (“rock; stone”), from Ancient Greek πέτρᾱ (pétrā, “rock formation; stone”)).

Clipping of blue peter (“play a high card to call for trump”). See further etymology there.