Al"der (#), 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.] Bot.
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.
Black alder. (a) A European shrub (Rhamnus frangula); Alder buckthorn. (b) An American species of holly (Ilex verticillata), bearing red berries.
© Webster 1913.
Al"der (#), Al"ler (#), 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.
[Obs.]
Chaucer.
© Webster 1913.