ribbon tree rib·bont·ree uncommon noun 1. deciduous New Zealand tree whose inner bark yields a strong fiber that resembles flax and is called New Zealand cotton Synonymsribbon treeribbonwoodPlagianthus regiusPlagianthus betulinus Related words Broader terms tree Parts Plagianthus Part of New Zealand cotton WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.