Definition of Forinsecus
Lat. Foreign; exterior; outside; extraordinary.
Servitium forinsecum, the payment of aid, scutage, and other extraordinary military services. Forinsecum manerium, the manor, or that part of it which lies outside the bars or town and is not included within the liberties of it.
That's the definition of Forinsecus in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.