bomber vs military plane

bomber and military plane both are nouns.

Word	Noun	Adjective	Verb	Adverb
bomber	Yes	No	No	No
military plane	Yes	No	No	No

As nouns, military plane is a hypernym of bomber; that is, military plane is a word with a broader meaning than bomber:

Other hypernyms of bomber include aeroplane, airplane, plane, warplane.

bomber (noun)	military plane (noun)
a military aircraft that drops bombs during flight	an aircraft designed and used for combat
a large sandwich made of a long crusty roll split lengthwise and filled with meats and cheese (and tomato and onion and lettuce and condiments); different names are used in different sections of the United States
a person who plants bombs