Feudum Antiquum
Defined in 2 dictionaries — Cyclopedic (1922), Black's (1891)
The Cyclopedic Law Dictionary
Walter A. Shumaker and George Foster Longsdorf; ed. James C. Cahill · 1922
A fee descended from the tenant's ancestors. 2 Bl. Comm. 212. One which had been possessed by the relations of the tenant for four generations. Spelman.
A Dictionary of Law
Henry Campbell Black · 1891
An ancien feud or fief; a fief descended to the vasga from his ancestors. 2 Bl. Comm. 212, 221, A fief which ancestors had possessed for ner than four generations. Spelman.