noun (n)

• a digestible substance used to give color to food(noun.food)

  Synonym:
  colouring, food color, food coloring, food colour, food colouring
  

  source: wordnet30
• a visual attribute of things that results from the light they emit or transmit or reflect(noun.attribute)

  Synonym:
  color, colour, colouring
  Antonym:
  achromaticity, achromatism, colorlessness, colourlessness
  

  source: wordnet30
• the act or process of changing the color of something(noun.act)

  Synonym:
  colouring
  

  source: wordnet30
• The act of applying color to; also, that which produces color.(noun)

  source: webster1913