where (adv.) Look up where at Dictionary.com
Old English hwær, hwar "at what place," from Proto-Germanic adverb *hwar (cognates: Old Saxon hwar, Old Norse hvar, Old Frisian hwer, Middle Dutch waer, Old High German hwar, German wo, Gothic hvar "where"), equivalent to Latin cur, from PIE interrogative base *kwo- (see who). Where it's at attested from 1903.