where (adv.) Look up where at Dictionary.com
Old English hwær, hwar "at what place," from Proto-Germanic adverb *hwar (source also of 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.