mountain alder moun·tai·nal·der uncommon noun 1. small shrubby maple of eastern North America; scarlet in autumn Synonymsmountain maplemountain alderAcer spicatum 2. tree of western United States Synonymswhite aldermountain alderAlnus rhombifolia Related words Broader terms aldermaple Parts Alnus WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
