The Collaborative International Dictionary of English v.0.48:

Lisp \Lisp\ (l[i^]sp), v. i. [imp. & p. p. Lisped (l[i^]spt);
   p. pr. & vb. n. Lisping.] [OE. lispen, lipsen, AS. wlisp
   stammering, lisping; akin to D. & OHG. lispen to lisp, G.
   lispeln, Sw. l[aum]spa, Dan. lespe.]
   1. To pronounce the sibilant letter s imperfectly; to give s
      and z the sound of th; -- a defect common among children.
      [1913 Webster]

   2. To speak with imperfect articulation; to mispronounce, as
      a child learning to talk.
      [1913 Webster]

            As yet a child, nor yet a fool to fame,
            I lisped in numbers, for the numbers came. --Pope.
      [1913 Webster]

   3. To speak hesitatingly with a low voice, as if afraid.
      [1913 Webster]

            Lest when my lisping, guilty tongue should halt.
                                                  --Drayton.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lisp \Lisp\, v. t.
   1. To pronounce with a lisp.
      [1913 Webster]

   2. 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.
      [1913 Webster]

            To speak unto them after their own capacity, and to
            lisp the words unto them according as the babes and
            children of that age might sound them again.
                                                  --Tyndale.
      [1913 Webster]

   3. To speak with reserve or concealment; to utter timidly or
      confidentially; as, to lisp treason.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lisp \Lisp\, n.
   The habit or act of lisping. See Lisp, v. i., 1.
   [1913 Webster]

         I overheard her answer, with a very pretty lisp, "O!
         Strephon, you are a dangerous creature." --Tatler.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

LISP \LISP\ (l[i^]sp), n. (Computers) [List Processing.]
   a high-level computer programming language in which
   statements and data are in the form of lists, enclosed in
   parentheses; -- used especially for rapid development of
   prototype programs in artificial intelligence applications .
   [PJC]

WordNet (r) 3.0 (2006):

lisp
    n 1: a speech defect that involves pronouncing `s' like
         voiceless `th' and `z' like voiced `th'
    2: a flexible procedure-oriented programing language that
       manipulates symbols in the form of lists [syn: LISP, list-
       processing language]
    v 1: speak with a lisp

Moby Thesaurus II by Grady Ward, 1.0:

90 Moby Thesaurus words for "lisp":
   aphonia, artificial voice, assibilate, assibilation, broken speech,
   broken tones, broken voice, buzz, childish treble, choked voice,
   cracked voice, croak, crow, drawl, dysarthria, dyslalia, dyslogia,
   dysphasia, dysphonia, dysphrasia, effervesce, effervescence,
   effervescing, falsetto, fizz, fizzle, fizzling, frication,
   frictional rustling, harshness, hawking voice, hiss, hissing,
   hoarseness, hush, hushing, idioglossia, idiolalia,
   impairment of speech, lisping, loss of voice, mince, muzzy speech,
   nasal tone, nasalization, quaver, rhonchus, shake, shush, shushing,
   sibilance, sibilate, sibilation, siffle, sigmatism, siss, sissing,
   sizz, sizzle, sizzling, sneeze, sneezing, sniff, sniffle, snore,
   snort, snuff, snuffle, speech defect, speech impediment, spit,
   splutter, sputter, squash, squelch, squish, sternutation, stertor,
   swish, talk incoherently, tremor, twang, wheeze, whish, whistle,
   whistling, white noise, whiz, whoosh, zip



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

LISP
       LISt Processor (LISP)


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

LISP
       Lots of Isolated Silly Parentheses (LISP, slang)


The Jargon File (version 4.4.7, 29 Dec 2003):

LISP
 n.

    [from ?LISt Processing language?, but mythically from ?Lots of Irritating
    Superfluous Parentheses?] AI's mother tongue, a language based on the ideas
    of (a) variable-length lists and trees as fundamental data types, and (b)
    the interpretation of code as data and vice-versa. Invented by John
    McCarthy at MIT in the late 1950s, it is actually older than any other HLL
     still in use except FORTRAN. Accordingly, it has undergone considerable
    adaptive radiation over the years; modern variants are quite different in
    detail from the original LISP 1.5. The dominant HLL among hackers until the
    early 1980s, LISP has since shared the throne with C. Its partisans claim
    it is the only language that is truly beautiful. See languages of choice.

    All LISP functions and programs are expressions that return values; this,
    together with the high memory utilization of LISPs, gave rise to Alan
    Perlis's famous quip (itself a take on an Oscar Wilde quote) that ?LISP
    programmers know the value of everything and the cost of nothing?.

    One significant application for LISP has been as a proof by example that
    most newer languages, such as COBOL and Ada, are full of unnecessary 
    crocks. When the Right Thing has already been done once, there is no
    justification for bogosity in newer languages.

    [lisp]

    We've got your numbers....


The Free On-line Dictionary of Computing (30 December 2018):

Lisp

    LISt Processing language.

   (Or mythically "Lots of Irritating Superfluous Parentheses").
   Artificial Intelligence's mother tongue, a symbolic,
   functional, recursive language based on the ideas of
   lambda-calculus, variable-length lists and trees as
   fundamental data types and the interpretation of code as data
   and vice-versa.

   Data objects in Lisp are lists and atoms.  Lists may contain
   lists and atoms.  Atoms are either numbers or symbols.
   Programs in Lisp are themselves lists of symbols which can be
   treated as data.  Most implementations of Lisp allow functions
   with side-effects but there is a core of Lisp which is
   purely functional.

   All Lisp functions and programs are expressions that return
   values; this, together with the high memory use of Lisp, gave
   rise to Alan Perlis's famous quip (itself a take on an Oscar
   Wilde quote) that "Lisp programmers know the value of
   everything and the cost of nothing".

   The original version was LISP 1, invented by John McCarthy
    at MIT in the late 1950s.  Lisp is
   actually older than any other high level language still in
   use except Fortran.  Accordingly, it has undergone
   considerable change over the years.  Modern variants are quite
   different in detail.  The dominant HLL among hackers until
   the early 1980s, Lisp now shares the throne with C.  See
   languages of choice.

   One significant application for Lisp has been as a proof by
   example that most newer languages, such as COBOL and Ada,
   are full of unnecessary crocks.  When the Right Thing has
   already been done once, there is no justification for
   bogosity in newer languages.

   See also Association of Lisp Users, Common Lisp, Franz
   Lisp, MacLisp, Portable Standard Lisp, Interlisp,
   Scheme, ELisp, Kamin's interpreters.

   [Jargon File]

   (1995-04-16)