The Collaborative International Dictionary of English v.0.48:

Terre-tenant \Terre"-ten`ant\, n. [F. terre earth, land +
   tenant, p. pr. of tenir to hold.] (Law)
   One who has the actual possession of land; the occupant.
   [Written also ter-tenant.]
   [1913 Webster]
   [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

TERRE-TENANT, or improperly terre-tenant. One who has the actual possession
of land; but in a more technical sense, he who is seised of the land; and,
in the latter sense the owner of the land, or the person seised, is the
terre-tenant, and not the lessee. 4 W. & S. 256; Bac. Ab. Uses and Trusts,
in pr. It has been holden that mere occupiers of the land are not terre-
tenants. Bee 16 S. & R, 432; 3 Penna. 229; 2 Saund. 7, n. 4; 2 Bl. Com. 91,
328.