lower berth vs lower

lower berth and lower both are nouns.

Word	Noun	Adjective	Verb	Adverb
lower berth	Yes	No	No	No
lower	Yes	Yes	Yes	No

As nouns, lower berth and lower are synonyms defined as:

lower berth (noun)	lower (noun)
the lower of two berths	the lower of two berths

lower berth (adjective)	lower (adjective)
	the bottom one of two

lower berth (verb)	lower (verb)
	make lower or quieter
	set lower
	cause to drop or sink
	move something or somebody to a lower position
	look angry or sullen, wrinkle one's forehead, as if to signal disapproval