a tree of several species, constituting the genus betula; as, the white or common birch (b. alba) (also called silver birch and lady birch); the dwarf birch (b. glandulosa); the paper or canoe birch (b. papyracea); the yellow birch (b. lutea); the black or cherry birch (b. lenta).-the wood or timber of the birch.-a birch twig or birch twigs, used for flogging.-a birch-bark canoe.-of or pertaining to the birch; birchen.-to whip with a birch rod or twig; to flog.