genus Ailanthus ge·nu·sai·lanthus uncommon noun 1. small genus of east Asian and Chinese trees with odd-pinnate leaves and long twisted samaras Synonymsgenus Ailanthus Related words Broader terms rosid dicot genus Parts Simaroubaceae Part of ailanthustree of heaven WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.