The period of time during which a contract conveying property to a person is in effect WordNet 3.0 & Open English WordNet

Agreement which gives rise to relationship of landlord and tenant (real property) or lessor and lessee (real or personal property). Contract for exclusive possession of lands or tenements for determinate period. Contract for possession and profits of lands and tenements either for life, or for certain period of time, or during the pleasure of the parties. OmegaWiki

The period of such a contract. Wiktionary

Period of such a contract. Wiktionary (translation)