Maianthemum maiant·he·mum uncommon noun 1. sometimes placed in family Convallariaceae: false lily of the valley Synonymsgenus Maianthemum Related words Word family Maianthemum bifoliumMaianthemum canadense Broader terms liliid monocot genus Parts Liliaceae Part of false lily of the valley WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.