interrogative
n. in linguistics, the form of a sentence used to pose a question rather than to make a statement, issue a command, and so on, or the mood of the verb used in such constructions. In English there are two main types of interrogative: yes/no questions (e.g., Are you going?) and wh- questions using what, when, where, who, and how (e.g., Where are you going?). Both types require the use of an auxiliary verb (usually be, have, or do). The structural relationships between the declarative and interrogative forms of a sentence are of major interest in generative grammar and psycholinguistics (see auxiliary inversion). Compare imperative; indicative; subjunctive.