From Middle English socke, sokke, sok, from Old English socc ("sock, light shoe, slipper"), a West Germanic borrowing from Latin soccus ("a light shoe or slipper, buskin"), from Ancient Greek σύκχος ("a kind of shoe"), probably from Phrygian or from an language. Cognate with Scots sok ("sock, stocking"), West Frisian foetsok ("sock"), Dutch sok ("sock"), German Socke ("sock"), Danish sok, sokke, Swedish sock, socka, Icelandic sokkur ("sock").
Onomatopoeic. Compare Portuguese soco ("a hit with one's hand; a punch").
From French soc, from Late Latin soccus, perhaps of Celtic origin.