PRIMER SEISIN, Eng. law. The right which the king had, when any of his
tenants died seised of a knight's fee, to receive of the heir, provided he
were of fall age, one whole year's profits of the lands, if they were in
immediate possession; and half a year's profits, if the lands were in
reversion, expectant on an estate for life. 2 Bl. Com. 66.