[syn: coloring, colouring]
The Collaborative International Dictionary of English v.0.48:
colouring \colouring\ n.
   same as coloring. [Brit.]
   [WordNet 1.5]
WordNet (r) 3.0 (2006):
colouring
    n 1: a digestible substance used to give color to food; "food
         color made from vegetable dyes" [syn: coloring,
         colouring, food coloring, food colouring, food
         color, food colour]
    2: 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]
    3: the act or process of changing the color of something [syn:
       coloring, colouring]