What does "alder" mean?

Alder: 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.

Additional senses

  1. 2.Of all; -- used in composition; as, alderbest, best of all, alderwisest, wisest of all. [Obs.] Chaucer.

Sources