- ailanthus [ā lan′thəs]n.pl. ailanthuses [ModL, altered (by assoc. with Gr anthos, flower) < ai lanit, lit., tree of heaven, the name in a language of Moluccas, Indonesia]any tree or shrub of a genus (Ailanthus) of the quassia family, having pointed leaflets, fine-grained wood, and clusters of small, greenish flowers with an unpleasant odor: see TREE OF HEAVENailanthicadj.
English World dictionary. V. Neufeldt. 2014.