firebase vs base of operations

firebase and base of operations both are nouns.

Word	Noun	Adjective	Verb	Adverb
firebase	Yes	No	No	No
base of operations	Yes	No	No	No

As nouns, base of operations is a hypernym of firebase; that is, base of operations is a word with a broader meaning than firebase:

firebase: an artillery base to support advancing troops
base of operations: installation from which a military force initiates operations

Other hypernyms of firebase include base.

firebase (noun)	base of operations (noun)
an artillery base to support advancing troops	installation from which a military force initiates operations