styyoudaoicibaDictYouDict[sty 词源字典]
sty: English has two distinct words sty. The ‘pig enclosure’ [OE] is not recorded for certain as an independent word before the 13th century, but it occurs in compounds in Old English, and it is probably the same word as Old English stig ‘hall’ (source of English steward). It goes back ultimately to a prehistoric Germanic *stijam. The sty on one’s eye [17] denotes etymologically a ‘swelling’.

It comes from the now defunct styany ‘sty’. This was misinterpreted as ‘sty-oneye’, but in fact it was a compound formed from Middle English styan ‘swelling’ (a descendant of the present participle of Old English stīgan ‘rise’, which is related to modern English stair and stirrup) and eye.
=> steward; eye, stair, stirrup[sty etymology, sty origin, 英语词源]
sty (n.1)youdaoicibaDictYouDict
"pen for pigs," Old English sti, stig "hall, pen" (as in sti-fearh "sty-pig"), from Proto-Germanic *stijan (cognates: Old Norse stia "sty, kennel," Danish sti, Swedish stia "pen for swine, sheep, goats, etc.," Old High German stiga "pen for small cattle"). Meaning "filthy hovel" is from 1590s.
sty (n.2)youdaoicibaDictYouDict
"inflamed swelling in the eyelid," 1610s, probably a back-formation from Middle English styany (as though sty on eye), mid-15c., from Old English stigend "sty," literally "riser," from present participle of stigan "go up, rise," from Proto-Germanic *stigan, from PIE root *steigh- "to stride, step, rise" (see stair).
sty (v.)youdaoicibaDictYouDict
"go up, ascend" (obsolete), Old English stigan (past tense stah, past participle stigun, common Germanic (Old Norse, Old Frisian stiga, Middle Dutch stighen, Old Saxon, Old High German stigan, German steigen, Gothic steigan), from PIE root *steigh- "go, rise, stride, step, walk" (see stair).