Apertura feudi, in ancient law books, denotes the loss of a feudal land tenure, by default of issue to him, to whom the feud or fee was first granted.

•  This article incorporates text from a publication now in the public domain: Chambers, Ephraim, ed. (1728). "Apertura feudi". Cyclopædia, or an Universal Dictionary of Arts and Sciences (1st ed.). James and John Knapton, et al.