built in bed vs berth

built in bed and berth both are nouns.

Word	Noun	Adjective	Verb	Adverb
built in bed	Yes	No	No	No
berth	Yes	No	Yes	No

As nouns, built in bed and berth are synonyms defined as:

Other synonyms of built in bed include bunk.

built in bed (noun)	berth (noun)
a bed on a ship or train; usually in tiers	a job in an organization
	a bed on a ship or train; usually in tiers
	a place where a craft can be made fast

built in bed (verb)	berth (verb)
	secure in or as if in a berth or dock
	come into or dock at a wharf
	provide with a berth