noun (n)

• an act of being a tenant or occupant(noun.act)

  Synonym:
  tenancy
  

  source: wordnet30
• the act of occupying or taking possession of a building(noun.act)

  Example:
  Occupation of a building without a certificate of occupancy is illegal.
  

  Synonym:
  moving in, occupation
  

  source: wordnet30
• The act of taking or holding possession; possession; occupation.(noun)

  source: webster1913