where
adv. placeadv. in or to what place. You use this word to ask about a location or to talk about where something is.
adv. at, in, or to which place or situation. Functions as an interrogative or relative adverb to specify location or destination.
Where do you live?
I am not sure where I left my keys this morning, but they are not on the table.
The researchers identified several key regions where the local climate had shifted significantly over the last decade, leading to a total loss of native vegetation.
Etymology tree Proto-Indo-European *kʷ- Proto-Indo-European *kʷís Proto-Germanic *hwaz Proto-Indo-European *-r Proto-Germanic *-r Proto-Germanic *hwar Proto-West Germanic *hwār Old English hwǣr Middle English wher English where From Middle English wher, from Old English hwǣr (“where”, literally “at what place”), from Proto-West Germanic hwār, from Proto-Germanic hwar (“where”), from Proto-Indo-European *kʷo- (interrogative pronoun).
Commonly used to introduce a question or a relative clause. When used in a relative clause, it refers back to a noun denoting a place.
The house where I live in is small.The house where I live is small.The word 'where' already includes the sense of 'in' or 'at'; adding a preposition like 'in' at the end of the clause is redundant.