De*lir"i*um (?), n. [L., fr. delirare to rave, to wander in mind, prop., to go out of the furrow in plowing; de- + lira furrow, track; perh. akin to G. geleise track, rut, and E. last to endure.] 1. (Med.) A state in which the thoughts, expressions, and actions are wild, irregular, and incoherent; mental aberration; a roving or wandering of the mind, -- usually dependent on a fever or some other disease, and so distinguished from mania, or madness.

2. Strong excitement; wild enthusiasm; madness.

The popular delirium [of the French Revolution] at first caught his enthusiastic mind.

W. Irving.

The delirium of the preceding session (of Parliament).

Morley.

Delirium tremens (&?;). [L., trembling delirium] (Med.), a violent delirium induced by the excessive and prolonged use of intoxicating liquors. -- Traumatic delirium(Med.), a variety of delirium following injury.

Syn. -- Insanity; frenzy; madness; derangement; aberration; mania; lunacy; fury. See Insanity.