WordNet (r) 3.0 (2006):

trespass quare clausum fregit
    n 1: the defendant unlawfully enters the land of the plaintiff

Bouvier's Law Dictionary, Revised 6th Ed (1856):

TRESPASS QUARE CLAUSUM FREGIT, practice. This is the name of a remedy which
lies to recover damages when the defendant has unlawfully and wrongfully
trespassed upon the real estate of the plaintiff.
     2. This action must be brought by the tenant in possession, for the
injury is done to his possession. A remainder-man or reversioner cannot
sustain it. 3. As the injury must be committed to the possession, one who
has a mere incorporeal right cannot maintain this action. 4 Bouv. Inst. n.
3600.