/aw tok"theuhn/ , n. , pl. autochthons, autochthones /-theuh neez'/ .
1. an aboriginal inhabitant.
2. Ecol. one of the indigenous animals or plants of a region.
3. Geol. a geological formation formed in the region where found. Cf. allochthon .
[ 1640-50; autóchthon of the land itself, equiv. to auto- AUTO- 1 + chthón the earth, land, ground ]