sock (n.) Look up sock at Dictionary.com
Old English socc "light slipper," a West Germanic borrowing from Latin soccus "light low-heeled shoe," variant of Greek sykchos "a kind of shoe," perhaps from Phrygian or another Asiatic language. To knock the socks off (someone) "beat thoroughly" is recorded from 1845, American English colloquial. Teen slang sock hop is c.1950, from notion of dancing without shoes.
sock (v.2) Look up sock at Dictionary.com
"to stash (money) away as savings," 1942, American English, from the notion of hiding one's money in a sock (see sock (n.)).
sock (v.1) Look up sock at Dictionary.com
1700, "to beat, hit," of uncertain origin. To sock it to (someone) first recorded 1877.