massed fire vs concentrated fire

massed fire and concentrated fire both are nouns.

Word	Noun	Adjective	Verb	Adverb
massed fire	Yes	No	No	No
concentrated fire	Yes	No	No	No

As nouns, massed fire and concentrated fire are synonyms defined as:

massed fire and concentrated fire: fire from two or more weapons directed at a single target or area (as fire by batteries of two or more warships)

massed fire (noun)	concentrated fire (noun)
fire from two or more weapons directed at a single target or area (as fire by batteries of two or more warships)	fire from two or more weapons directed at a single target or area (as fire by batteries of two or more warships)