sei·sin or sei·zin /'sēz-ən/ n [Anglo-French seisine, from Old French saisine act of taking possession, from saisir to seize, of Germanic origin]
1: the possession of land or chattels: as
a: the possession of land arising from livery of seisin see also livery of seisin
b: the possession of a freehold estate in land by one having title thereto
2: the right to immediate possession of an estate or to immediate succession
seisin of an heir upon death of the testator
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.