'autochthonousness' originates from Greek, specifically the word 'autochthonos' (from 'autochthōn'), where 'autos' meant 'self' and 'khthōn' (or 'chthon') meant 'earth/ground'.

'autochthonous' was borrowed into English via New Latin/Medieval Latin (e.g. New Latin 'autochthōnus'); the abstract noun was later formed in English by adding the suffix '-ness' to create 'autochthonousness'.

Initially it meant 'sprung from the land' or 'native to the soil'; over time it has come to be used as an abstract noun meaning 'the condition or quality of being indigenous' with largely the same core sense.