Unity of seisin
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
where a person seised of land which is subj'ect to an easement, profit a prender, or similar right, also becomes seised of the land to which the easement or other right is annexed. Sweet.
— Unity of time. One of the essential properties of a joint estate; the estates of the tenants being vested at one and the same period. 2 Bl. Comm. 181.
Defined under Unity in Black's Law Dictionary.