Alder \Al"der\ ([add]l"d[~e]r), 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.

Source: Webster's Revised Unabridged Dictionary (1913)