Emily Dickinson Lexicon

DE-LIR'I-UM, n. [L. from deliro, to wander in mind, to rave; de and liro, to make balks in plowing, that is, to err, wander, miss.]

A state in which the ideas of a person are wild, irregular, and unconnected, or do not correspond with the truths or with external objects; a roving or wandering of the mind; disorder of the intellect. Fevers often produce delirium. An alienation of mind connected with fever. – Cyc. Symptomatic derangement, or that which is dependent on some other disease, in distinction from idiopathic derangement or mania.