sock n.1

"knitted or woven covering for the foot, short stocking," Middle English sok, from Old English socc "slipper, light shoe," from Latin soccus "slipper, light low-heeled shoe," probably a variant of Greek sykkhos, word for a kind of shoe, perhaps from Phrygian or another Asiatic language. Beekes pointes to a source that "supposes a loan from the Caucasus, which may also be found in Av[estan] haxa- [n.] 'sole of the foot' ...." The Latin word was borrowed generally in West Germanic (Middle Dutch socke, Dutch sok, Old High German soc, German Socke).

Also in reference to the kind of light shoe worn by ancient actors in comedy, hence, in phrases, sock as "comedy" as distinct from "tragedy" (represented by buskin). To knock the socks off (someone) "beat thoroughly" is recorded from 1845, American English colloquial. Colloquial put a sock in it "stop speaking" is by 1919. Teen slang sock hop is c. 1950, from dancing shoeless.

1700, "to beat, hit hard, pitch into," of uncertain origin, perhaps imitative (compare bop, smack, slog, etc.). To sock it to (someone) "strike hard," literally or figuratively, is by 1877.

"to stash (money) as savings," 1942, American English, often with away, from the notion of hiding one's money in a sock (see sock (n.1)). A sock as a receptacle for storing money is alluded to by 1930.

"a blow, a hit with the fist," 1700, from or related to sock (v.1). Extended form socko is by 1924; further extended form sockeroo is by 1942.