birch

Concise Oxford English Dictionary © 2008 Oxford University Press:
birch/bɜːtʃ/

▶noun

• 1 a slender hardy tree with thin, peeling, silver-grey or white bark, which yields a hard pale wood. [Betula pendula (silver birch) and related species.]

• 2 (the birch) historical a formal punishment in which a person was flogged with a bundle of birch twigs.

▶verb historical beat with the birch as a punishment.

– derivatives
birchen adjective (archaic).

– origin OE bierce, birce, of Gmc origin.