genus Erythroxylon ge·nu·se·rythroxylon uncommon noun 1. a large genus of South American shrubs and small trees of the family Erythroxylaceae SynonymsErythroxylongenus ErythroxylonErythroxylumgenus Erythroxylum Related words Broader terms plant genus Part of Erythroxylon cocaErythroxylon truxiuense WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.