the birch

: any of a genus (Betula of the family Betulaceae, the birch family) of monoecious deciduous trees or shrubs having simple petioled leaves and typically a layered membranous outer bark that peels readily

: the hard pale close-grained wood of a birch

: a birch rod or bundle of twigs for flogging

: to beat with or as if with a birch : whip