The Collaborative International Dictionary
Purpresture
Purpresture \Pur*pres"ture\, n. [Probably corrupted (see Prest) fr. OF. pourprisure, fr. pourprendre: cf. LL. purprestura. Cf. Purprise.] (Law) Wrongful encroachment upon another's property; esp., any encroachment upon, or inclosure of, that which should be common or public, as highways, rivers, harbors, forts, etc.
Wiktionary
purpresture
n. The unlawful personal appropriation of public lands; wrongful encroachment on, or enclosure of properties belonging to the public (e.g. highways, sidewalks, forests, harbors).