The term originally referred to the completion of feudal investiture by which a tenant was admitted into the field to render services to the lord or proprietor. Today, it has come to mean possession under a legal right (usually a fee interest

possession (but not ownership) of land; the exercise and enjoyment of rights deriving from possession, usually of land, held as a freehold (but not as a serf's tenure). To be "in seisin" was to be "seized of" control of such an estate or other freehold rights. Livery of seisin (i.e., the delivery of seisin by a lord) was usually by some symbolic act. To be disseised was to be ousted from seisin.

Possession of real property under claim of freehold estate. This term originally referred to the completion of feudal investiture by which a tenant was admitted into the feud and performed the rights of homage and fealty. Presently it has come to mean possession under a legal right (usually a fee interest). As the old doctrine of corporeal investiture is no longer in force, the delivery of a deed gives seisin in law.