autochthon n.

word-forming element meaning "self, one's own, by oneself, of oneself" (and especially, from 1895, "automobile"), from Greek autos, reflexive pronoun, "self, same," which is of unknown origin. It also was a common word-forming element in ancient Greek, as in modern English, but very few of the old words have survived the interval. In Greek, as a word-forming element, auto- had the sense of "self, one's own, of oneself ('independently'); of itself ('natural, native, not made'); just exactly; together with." Before a vowel, it became aut-; before an aspirate, auth-. In Greek it also was used as a prefix to proper names, as in automelinna "Melinna herself." The opposite prefix would be allo-.

Proto-Indo-European root meaning "earth."

It forms all or part of: antichthon; autochthon; autochthonic; bonhomie; bridegroom; camomile; chameleon; chernozem; chthonic; exhume; homage; hombre; homicide; hominid; Homo sapiens; homunculus; human; humane; humble; humiliate; humility; humus; inhumation; inhume; nemo; ombre; omerta.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit ksam- "earth" (opposed to "sky"); Greek khthōn "the earth, solid surface of the earth," khamai "on the ground;" Latin humus "earth, soil," humilis "low;" Lithuanian žemė, Old Church Slavonic zemlja "earth;" Old Irish du, genitive don "place," earlier "earth."