interrogationn.[L. interrogatio: cf. F. interrogation.]()1. The act or process of interrogating or questioning; examination by questions; an instance of interrogating; inquiry.()2. A question put; an inquiry.()3. A point, mark, or sign, thus [?], indicating that the sentence with which it is connected is a question. It is used to express doubt, or to mark a query. Usually called a question mark; called also interrogation point.()()