The Collaborative International Dictionary of English v.0.48:
Autochthony \Au*toch"tho*ny\, n. An aboriginal or autochthonous condition. [1913 Webster]WordNet (r) 3.0 (2006):
autochthony n 1: nativeness by virtue of originating or occurring naturally (as in a particular place) [syn: indigenousness, autochthony, endemism]