The Collaborative International Dictionary of English v.0.48:
Territoriality \Ter`ri*to`ri*al"i*ty\ n. (Zool.) a pattern of behavior characterized by the marking and defense of a home territory, exhibited by certain male animals. [WordNet 1.5 +PJC]WordNet (r) 3.0 (2006):
territoriality n 1: the behavior of a male animal that defines and defends its territory