The Collaborative International Dictionary of English v.0.48:

Colour \Col"our\, n.
   See Color. [Brit.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Color \Col"or\ (k[u^]l"[~e]r), n. [Written also colour.] [OF.
   color, colur, colour, F. couleur, L. color; prob. akin to
   celare to conceal (the color taken as that which covers). See
   Helmet.]
   1. A property depending on the relations of light to the eye,
      by which individual and specific differences in the hues
      and tints of objects are apprehended in vision; as, gay
      colors; sad colors, etc.
      [1913 Webster]

   Note: The sensation of color depends upon a peculiar function
         of the retina or optic nerve, in consequence of which
         rays of light produce different effects according to
         the length of their waves or undulations, waves of a
         certain length producing the sensation of red, shorter
         waves green, and those still shorter blue, etc. White,
         or ordinary, light consists of waves of various lengths
         so blended as to produce no effect of color, and the
         color of objects depends upon their power to absorb or
         reflect a greater or less proportion of the rays which
         fall upon them.
         [1913 Webster]

   2. Any hue distinguished from white or black.
      [1913 Webster]

   3. The hue or color characteristic of good health and
      spirits; ruddy complexion.
      [1913 Webster]

            Give color to my pale cheek.          --Shak.
      [1913 Webster]

   4. That which is used to give color; a paint; a pigment; as,
      oil colors or water colors.
      [1913 Webster]

   5. That which covers or hides the real character of anything;
      semblance; excuse; disguise; appearance.
      [1913 Webster]

            They had let down the boat into the sea, under color
            as though they would have cast anchors out of the
            foreship.                             --Acts xxvii.
                                                  30.
      [1913 Webster]

            That he should die is worthy policy;
            But yet we want a color for his death. --Shak.
      [1913 Webster]

   6. Shade or variety of character; kind; species.
      [1913 Webster]

            Boys and women are for the most part cattle of this
            color.                                --Shak.
      [1913 Webster]

   7. A distinguishing badge, as a flag or similar symbol
      (usually in the plural); as, the colors or color of a ship
      or regiment; the colors of a race horse (that is, of the
      cap and jacket worn by the jockey).
      [1913 Webster]

            In the United States each regiment of infantry and
            artillery has two colors, one national and one
            regimental.                           --Farrow.
      [1913 Webster]

   8. (Law) An apparent right; as where the defendant in
      trespass gave to the plaintiff an appearance of title, by
      stating his title specially, thus removing the cause from
      the jury to the court. --Blackstone.
      [1913 Webster]

   Note: Color is express when it is averred in the pleading,
         and implied when it is implied in the pleading.
         [1913 Webster]

   Body color. See under Body.

   Color blindness, total or partial inability to distinguish
      or recognize colors. See Daltonism.

   Complementary color, one of two colors so related to each
      other that when blended together they produce white light;
      -- so called because each color makes up to the other what
      it lacks to make it white. Artificial or pigment colors,
      when mixed, produce effects differing from those of the
      primary colors, in consequence of partial absorption.

   Of color (as persons, races, etc.), not of the white race;
      -- commonly meaning, esp. in the United States, of negro
      blood, pure or mixed.

   Primary colors, those developed from the solar beam by the
      prism, viz., red, orange, yellow, green, blue, indigo, and
      violet, which are reduced by some authors to three, --
      red, green, and violet-blue. These three are sometimes
      called fundamental colors.

   Subjective color or Accidental color, a false or spurious
      color seen in some instances, owing to the persistence of
      the luminous impression upon the retina, and a gradual
      change of its character, as where a wheel perfectly white,
      and with a circumference regularly subdivided, is made to
      revolve rapidly over a dark object, the teeth of the wheel
      appear to the eye of different shades of color varying
      with the rapidity of rotation. See Accidental colors,
      under Accidental.
      [1913 Webster]

WordNet (r) 3.0 (2006):

colour
    adj 1: having or capable of producing colors; "color film"; "he
           rented a color television"; "marvelous color
           illustrations" [syn: color, colour] [ant: black and
           white(p), black-and-white]
    n 1: any material used for its color; "she used a different
         color for the trim" [syn: coloring material, colouring
         material, color, colour]
    2: a race with skin pigmentation different from the white race
       (especially Blacks) [syn: color, colour, people of
       color, people of colour]
    3: (physics) the characteristic of quarks that determines their
       role in the strong interaction; "each flavor of quarks comes
       in three colors" [syn: color, colour]
    4: interest and variety and intensity; "the Puritan Period was
       lacking in color"; "the characters were delineated with
       exceptional vividness" [syn: color, colour, vividness]
    5: the timbre of a musical sound; "the recording fails to
       capture the true color of the original music" [syn: color,
       colour, coloration, colouration]
    6: a visual attribute of things that results from the light they
       emit or transmit or reflect; "a white color is made up of
       many different wavelengths of light" [syn: color, colour,
       coloring, colouring] [ant: achromaticity,
       achromatism, colorlessness, colourlessness]
    7: an outward or token appearance or form that is deliberately
       misleading; "he hoped his claims would have a semblance of
       authenticity"; "he tried to give his falsehood the gloss of
       moral sanction"; "the situation soon took on a different
       color" [syn: semblance, gloss, color, colour]
    8: the appearance of objects (or light sources) described in
       terms of a person's perception of their hue and lightness (or
       brightness) and saturation [syn: color, colour]
    v 1: modify or bias; "His political ideas color his lectures"
         [syn: color, colour]
    2: decorate with colors; "color the walls with paint in warm
       tones" [syn: color, colour, emblazon]
    3: give a deceptive explanation or excuse for; "color a lie"
       [syn: color, colour, gloss]
    4: affect as in thought or feeling; "My personal feelings color
       my judgment in this case"; "The sadness tinged his life"
       [syn: tinge, color, colour, distort]
    5: add color to; "The child colored the drawings"; "Fall colored
       the trees"; "colorize black and white film" [syn: color,
       colorize, colorise, colourise, colourize, colour,
       color in, colour in] [ant: discolor]
    6: change color, often in an undesired manner; "The shirts
       discolored" [syn: discolor, discolour, colour, color]

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

colour
color

    (US "color") Colours are usually represented as
   RGB triples in a digital image because this corresponds
   most closely to the electronic signals needed to drive a
   CRT.  Several equivalent systems ("colour models") exist,
   e.g. HSB.  A colour image may be stored as three separate
   images, one for each of red, green, and blue, or each pixel
   may encode the colour using separate bit-fields for each
   colour component, or each pixel may store a logical colour
   number which is looked up in a hardware colour palette to
   find the colour to display.

   Printers may use the CMYK or Pantone representations of
   colours as well as RGB.

   (1999-08-02)