1. (a.) Expressed in the form of a question; as, an interrogative sentence; an interrogative pronoun\.

2. (n.) A word used in asking questions; as, who? which? why?

bone of contention catechism cross-interrogatory cross-question debating point demand feeler inquiry interrogation interrogatory issue leader leading question moot point point at issue point in question problem query question question at issue question mark quodlibet topic trial balloon vexed question