au·toch·tho·nous (ô-tŏkthə-nəs) also au·toch·tho·nal (-thə-nəl) or au·toch·thon·ic (ô′tŏk-thŏnĭk)
1. Originating or formed in the place where found; indigenous: autochthonous rocks; an autochthonous people; autochthonous folk tales. See Synonyms at native.
2. Ecology Native to or produced within a system: an autochthonous species; algae that provide an autochthonous source of nutrients in a lake.
au·tochthon·ism, au·tochtho·ny n.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.