From PIE *kwor (at what place) — part of a hidden triad with 'there' and 'here,' mirroring 'when/then/now.'
In or to what place or position; at, in, or to which.
From Old English 'hwǣr' (where, at what place), from Proto-Germanic *hwar, from PIE *kʷór or *kʷo- with a locative suffix. Built on the interrogative stem *kʷó- with an adverbial element indicating place. Cognate with Latin 'cūr' (why — originally 'at what point'), Gothic 'ƕar' (where), and Old Norse 'hvar.' The related forms 'there' (at that place) and 'here' (at this place) use the same place-marking suffix with demonstrative stems instead of the interrogative. Key roots: *kʷó- (Proto-Indo-European: "interrogative stem (who, what) + locative element").
'Where,' 'there,' and 'here' are built on the same structural template: interrogative-place, demonstrative-place, proximal-place. 'Where' asks 'at what place?'; 'there' answers 'at that place'; 'here' answers 'at this place.' English has a hidden grammatical architecture in its spatial adverbs, and the same triad appears in 'when/then/now' for time.