- so (adv.)
- Old English swa, swæ "in this way," from Proto-Germanic *swa (cf. Old Saxon, Middle Dutch, Old High German so, Old Norse sva, Danish saa, Swedish så, Old Frisian sa, Dutch zo, German so "so," Gothic swa "as"), from PIE reflexive pronomial stem *s(w)o- (cf. Greek hos "as," Old Latin suad "so," Latin se "himself").
The adverb so at the beginning of a sentence ('So I'll pay for it!'), probably of Yiddish origin, occurs frequently in conversation. [M.Pei, "Story of English," 1952]
So? as a term of dismissal is attested from 1886 (short for is that so?); so what as an exclamation of indifference dates from 1934. So-so "mediocre" is from 1520s; so-and-so is from 1596 meaning "something unspecified;" first recorded 1897 as a euphemistic term of abuse.