LISP > define

A speech defect that involves pronouncing `s' like voiceless `th' and `z' like voiced `th'.
A flexible procedure-oriented programing language that manipulates symbols in the form of lists.
- synonyms: list-processing language

(v.i.) To speak with imperfect articulation; to mispronounce, as a child learning to talk.
(v.t.) To utter with imperfect articulation; to express with words pronounced imperfectly or indistinctly, as a child speaks; hence, to express by the use of simple, childlike language.
(v.t.) To speak with reserve or concealment; to utter timidly or confidentially; as, to lisp treason.
(v.i.) To pronounce the sibilant letter s imperfectly; to give s and z the sound of th; -- a defect common among children.
(v.i.) To speak hesitatingly with a low voice, as if afraid.
(n.) The habit or act of lisping. See Lisp, v. i., 1.
(v.t.) To pronounce with a lisp.

by Webster's Revised Unabridged Dictionary

LISP is a programming language based on predicate logic and is the one most commonly used in artificial intelligence applications.