c. 1600, from Anglo-French floteson, from Old French flotaison "a floating" (Modern French flottaison), from floter "to float, set afloat" (of Germanic origin and cognate with float) + -aison, from Latin -ation(em). Spelled flotsen in English till mid-19c. when it altered, perhaps under influence of many English words in -some. Folk-etymologized in dialect as floatsome.
In British law, flotsam are goods found floating on the sea as a consequence of a shipwreck or action of wind or waves; jetsam are things cast out of a ship in danger of being wrecked, and afterward washed ashore, or things cast ashore by the sailors. Whatever sinks is lagan. Flotsam and jetsam figuratively for "odds and ends" is attested by 1861.
1560s, jottsome "act of throwing goods overboard to lighten a ship," alteration and contraction of Middle English jetteson, from Anglo-French getteson, Old French getaison "a throwing" (see jettison). Intermediate forms were jetson, jetsome; the form perhaps was deformed by influence of flotsam. From 1590s as "goods thrown overboard;" figurative use by 1861. For distinction of meaning, see flotsam.
Proto-Indo-European root meaning "to flow."
It forms all or part of: fletcher; fledge; flee; fleet (adj.) "swift;" fleet (n.2) "group of ships under one command;" fleet (v.) "to float, drift; flow, run;" fleeting; flight (n.1) "act of flying;" flight (n.2) "act of fleeing;" flit; float; flood; flotsam; flotilla; flow; flue; flugelhorn; fluster; flutter; fly (v.1) "move through the air with wings;" fly (n.) "winged insect;" fowl; plover; Pluto; plutocracy; pluvial; pneumo-; pneumonia; pneumonic; pulmonary.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit plavate "navigates, swims;" Greek plynein "to wash," plein "to navigate," ploein "to float, swim," plotos "floating, navigable," pyelos "trough, basin;" Latin plovere "to rain," pluvius "rainy;" Armenian luanam "I wash;" Old English flowan "to flow;" Old Church Slavonic plovo "to flow, navigate;" Lithuanian pilu, pilti "to pour out," plauju, plauti "to swim, rinse."
early 13c., "goods cast ashore after a shipwreck, flotsam," from Anglo-French wrec, from a Scandinavian source akin to Old Norse *wrek "wreck, flotsam" (source also of Norwegian, Icelandic rek), related to reka "to drive, push," from Proto-Germanic *wrekan (see wreak (v.)). The meaning "a shipwreck" is first recorded mid-15c.; that of "a wrecked ship" is by c. 1500. General sense of "remains of anything that has been ruined" is recorded from 1713; applied by 1795 to dissipated persons. Compare wrack (v.).
late 14c., "unclaimed property, flotsam, stray animal," from Anglo-French waif (13c., Old French guaif) "ownerless property, something lost;" as an adjective, "not claimed, outcast, abandoned," probably from a Scandinavian source akin to Old Norse veif "waving thing, flag," from Proto-Germanic *waif-, from PIE root *weip- "to turn, vacillate, tremble ecstatically." Compare Medieval Latin waivium "thing thrown away by a thief in flight." A Scottish/northern English parallel form was wavenger (late 15c.).
Meaning "person (especially a child) without home or friends" first attested 1784, from legal phrase waif and stray (1620s), from the adjective in the sense "lost, strayed, homeless." Neglected children being uncommonly thin, the word tended toward this sense. Connotations of "fashionable, small, slender woman" began 1991 with application to childishly slim supermodels such as Kate Moss.