noun (n)

• a small contrasting part of something(noun.attribute)

  Synonym:
  dapple, fleck, patch, speckle, spot
  

  source: wordnet30
• the act of spotting or staining something(noun.act)

  Synonym:
  spotting, staining
  

  source: wordnet30
• The act of spotting; a spot; a blemish.(noun)

  source: webster1913