n. The popular name of shrubs and trees belonging to the genus Alnus, natural order Cupuliferæ.n. A name of species of other widely different genera, from their resemblance to true alders.n. An old form of elder.The Middle English genitive plural of all.n. A shrub of the genus Fothergilla, of the southeastern United States.n. Alnus rhombifolia, of the western United States.n. The striped maple, Acer Pennsylvanicum.