occupancy

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act of occupying or the condition of being occupied.
• noun The state of being an occupant or tenant.
• noun The period during which one owns, rents, or uses certain premises or land.
• noun The use to which something occupied is put.
• noun Law The act of taking possession of previously unowned property with the intent of obtaining the right to own it.

from The Century Dictionary.

• noun The act of taking possession, or the being in actual possession; more specifically, in law, the taking possession of a thing not belonging to any person, and the right acquired by such act; that mode of acquiring property which is founded on the principle that he who takes possession of an ownerless thing, with the design of appropriating it to himself, thereby becomes the owner of it; the act of occupying or holding in actual as distinguished from constructive possession.
• noun The term during which one is an occupant: as, during his occupancy of the post.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of taking or holding possession, especially of real property or rental property; possession; occupation.
• noun The state or condition of being occupied.
• noun The period of time during which one occupies a property.
• noun (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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The act of occupying, the state of being occupied or the state of being an occupant or tenant
• noun The period of time during which someone rents or otherwise occupies certain land or premises
• noun The specific use to which something occupied is put

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the act of occupying or taking possession of a building
• noun an act of being a tenant or occupant