alder, n. [OE. aldir, aller, fr. AS. alr, aler, alor, akin to D. els, G. erle, Icel. erlir, erli, Swed. al, Dan. elle, el, L. alnus, and E. elm.].
Black alder. (a) A European shrub (Rhamnus frangula); Alder buckthorn. (b) An American species of holly (Ilex verticillata), bearing red berries.
A tree, usually growing in moist land, and belonging to the genus Alnus. The wood is used by turners, etc.; the bark by dyers and tanners. In the U. S. the species of alder are usually shrubs or small trees. [1913 Webster]
alder, a. [From ealra, alra, gen. pl. of AS. eal. The d is excrescent.].
Of all; -- used in composition; as, alderbest, best of all, alderwisest, wisest of all. Chaucer. [1913 Webster]