Seisin Law and Legal Definition
Seisin is an an old English property term for having both possession and title of real property. An owner was not originally said to have ownership, but to be "seised of" property, since all land was technically considered to be owned by the sovereign. Seisin referred to more than mere possession of property, but also the right to transfer property by "livery of seisin". Today the term means ownership of full title to real property.