Mastotermes mas·to·ter·mes uncommon noun 1. primitive genus of termites; mostly extinct; sometimes considered the most primitive Isoptera Synonymsgenus Mastotermes Related words Word family Mastotermes darwiniensisMastotermes electrodominicusMastotermes electromexicus Broader terms arthropod genus Parts Mastotermitidae Part of Mastotermes darwiniensisMastotermes electromexicusMastotermes electrodominicus WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.