lab bench vs laboratory bench

lab bench and laboratory bench both are nouns.

Word	Noun	Adjective	Verb	Adverb
lab bench	Yes	No	No	No
laboratory bench	Yes	No	No	No

As nouns, lab bench and laboratory bench are synonyms defined as:

lab bench (noun)	laboratory bench (noun)
a workbench in a laboratory	a workbench in a laboratory