The Collaborative International Dictionary of English v.0.48:

Ideal \I*de"al\, n.
   A mental conception regarded as a standard of perfection; a
   model of excellence, beauty, etc.
   [1913 Webster]

         The ideal is to be attained by selecting and assembling
         in one whole the beauties and perfections which are
         usually seen in different individuals, excluding
         everything defective or unseemly, so as to form a type
         or model of the species. Thus, the Apollo Belvedere is
         the ideal of the beauty and proportion of the human
         frame.                                   --Fleming.
   [1913 Webster]

   Beau ideal. See Beau ideal.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ideal \I*de"al\, a. [L. idealis: cf. F. id['e]al.]
   1. Existing in idea or thought; conceptional; intellectual;
      mental; as, ideal knowledge.
      [1913 Webster]

   2. Reaching an imaginary standard of excellence; fit for a
      model; faultless; as, ideal beauty. --Byron.
      [1913 Webster]

            There will always be a wide interval between
            practical and ideal excellence.       --Rambler.
      [1913 Webster]

   3. Existing in fancy or imagination only; visionary; unreal.
      "Planning ideal common wealth." --Southey.
      [1913 Webster]

   4. Teaching the doctrine of idealism; as, the ideal theory or
      philosophy.
      [1913 Webster]

   5. (Math.) Imaginary.

   Syn: Intellectual; mental; visionary; fanciful; imaginary;
        unreal; impracticable; utopian.
        [1913 Webster]

WordNet (r) 3.0 (2006):

ideal
    adj 1: conforming to an ultimate standard of perfection or
           excellence; embodying an ideal
    2: constituting or existing only in the form of an idea or
       mental image or conception; "a poem or essay may be typical
       of its period in idea or ideal content"
    3: of or relating to the philosophical doctrine of the reality
       of ideas [syn: ideal, idealistic]
    n 1: the idea of something that is perfect; something that one
         hopes to attain
    2: model of excellence or perfection of a kind; one having no
       equal [syn: ideal, paragon, nonpareil, saint,
       apotheosis, nonesuch, nonsuch]

The Free On-line Dictionary of Computing (19 January 2023):

IDEAL

   1. Ideal DEductive Applicative Language.  A language by Pier
   Bosco and Elio Giovannetti combining Miranda and Prolog.
   Function definitions can have a guard condition (introduced
   by ":-") which is a conjunction of equalities between
   arbitrary terms, including functions.  These guards are solved
   by normal Prolog resolution and unification.  It was
   originally compiled into C-Prolog but was eventually to be
   compiled to K-leaf.

   2. A numerical constraint language written by Van Wyk of
   Stanford in 1980 for typesetting graphics in documents.
   It was inspired partly by Metafont and is distributed as
   part of Troff.

   ["A High-Level Language for Specifying Pictures", C.J. Van
   Wyk, ACM Trans Graphics 1(2):163-182 (Apr 1982)].

   (1994-12-15)


The Free On-line Dictionary of Computing (19 January 2023):

ideal

    In domain theory, a non-empty, downward closed
   subset which is also closed under binary least upper bounds.
   I.e. anything less than an element is also an element and the
   least upper bound of any two elements is also an element.

   (1997-09-26)