usucaption
Concise Oxford English Dictionary © 2008 Oxford University Press:
usucaption /ˌjuːzjʊˈkapʃ(ə)n/ (also usucapion /ˌjuːzjʊˈkeɪpɪən/)
▶noun Roman Law, chiefly historical the acquisition of a title or right to property by uninterrupted and undisputed possession for a prescribed term.
– origin C17: from med. L. usucaptio(n-), from usucapere ‘acquire by prescription’.
'usucaption' also found in these Oxford entries:

