stand in with

Old English standan (class VI strong verb; past tense stod, past participle standen), from Proto-Germanic *sta-n-d- (cf. Old Norse standa, Old Saxon and Gothic standan, Old High German stantan, Swedish stå, Dutch staan, German stehen), from PIE root *sta- "to stand" (see stet).

Sense of "to exist, be present" is attested from c.1300. Meaning "to pay for as a treat" is from 1821. Phrase stands to reason (1620) is from earlier stands (is constant) with reason. Phrase stand pat is originally from poker (1882); stand down in the military sense of "go off duty" is first recorded 1916. Standing ovation attested by 1968; standing army is from c.1600.