Originating where found; indigenous: autochthonous rocks; an autochthonous people; autochthonous folktales. See Synonyms at native.
Biology Originating or formed in the place where found: an autochthonous blood clot.
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.