noun (n)

• any number of entities (members) considered as a unit(noun.tops)

  Synonym:
  group
  

  source: wordnet30
• the activity of putting things together in groups(noun.act)

  source: wordnet30
• a system for classifying things into groups(noun.cognition)

  Synonym:
  pigeonholing
  

  source: wordnet30
• The disposal or relative arrangement of figures or objects, as in, drawing, painting, and sculpture, or in ornamental design.(noun)

  source: webster1913