An
interrogative word or
question word is a
function word used to ask a
question, such as
what,
when,
where,
who,
whom,
why, and
how. They are sometimes called
wh-words, because in
English most of them start with
wh- (compare
Five Ws). They may be used in both direct questions (
Where is he going?) and in
indirect questions (
I wonder where he is going). In English and various other languages the same forms are also used as
relative pronouns in certain
relative clauses (
The country where he was born) and certain
adverb clauses (
I go where he goes).