Source : Webster's Revised Unabridged Dictionary (1913)

Occupancy \Oc"cu*pan*cy\, n. [See {Occupant}.]
   The act of taking or holding possession; possession;
   occupation.

   {Title by occupancy} (Law), a right of property acquired by
      taking the first possession of a thing, or possession of a
      thing which belonged to nobody, and appropriating it.
      --Blackstone. Kent.

Source : WordNet®

occupancy
     n 1: an act of being a tenant or occupant [syn: {tenancy}]
     2: the act of occupying or taking possession of a building;
        "occupation of a building without a certificate of
        occupancy is illegal" [syn: {occupation}, {taking
        possession}, {moving in}]