The Collaborative International Dictionary of English v.0.48:

Delirium \De*lir"i*um\ (d[-e]*l[i^]r"[i^]*[u^]m), 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.
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   2. Strong excitement; wild enthusiasm; madness.
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            The popular delirium [of the French Revolution] at
            first caught his enthusiastic mind.   --W. Irving.
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            The delirium of the preceding session (of
            Parliament).                          --Morley.
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   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.
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