(law, formal) An estate in land held under a lease which is not perpetual or indefinite in length, though in some cases may be contingent on some guaranteed occurrence.

plural of term of years

(law, England & Wales, formal, misleading) An estate in land held for a term of years of either a specified length or on a periodic basis, and which is not a term of years determinable (though may be determinable for other reasons); a leasehold estate in land.

(law, England & Wales, formal, historical) An estate in land held for a term of years which determined on the deaths of certain individuals, or the cessation of certain life interests.