military band vs concert band

military band and concert band both are nouns.

Word	Noun	Adjective	Verb	Adverb
military band	Yes	No	No	No
concert band	Yes	No	No	No

As nouns, military band and concert band are synonyms defined as:

military band and concert band: a group of musicians playing brass and woodwind and percussion instruments

military band (noun)	concert band (noun)
a group of musicians playing brass and woodwind and percussion instruments	a group of musicians playing brass and woodwind and percussion instruments