Meaning

noun a long trough for feeding cattle

noun a bed on a ship or train; usually in tiers

noun a rough bed (as at a campsite)

originSense of sleeping berth possibly from Scottish English bunker (“seat, bench”), origin is uncertain but possibly Scandinavian Compare Old Swedish bunke (“boards used to protect the cargo of a ship”). See also boarding, flooring and compare bunch.

Etymology from Wiktionary, CC BY-SA 3.0