bunk

Concise Oxford English Dictionary © 2008 Oxford University Press:
bunk1

▶noun a narrow shelf-like bed. ▶verb chiefly N. Amer. sleep in a bunk or improvised bed in shared quarters.

– origin C18: of unknown origin; perh. rel. to bunker.

Concise Oxford English Dictionary © 2008 Oxford University Press:
bunk2

▶verb (bunk off) Brit. informal abscond from school or work.

– phrases
do a bunk make a hurried departure.

– origin C19: of unknown origin.

Concise Oxford English Dictionary © 2008 Oxford University Press:
bunk3

▶noun informal, dated nonsense.

– origin early 20th cent.: abbrev. of bunkum.