naval forces vs armed service

naval forces and armed service both are nouns.

Word	Noun	Adjective	Verb	Adverb
naval forces	Yes	No	No	No
armed service	Yes	No	No	No

As nouns, armed service is a hypernym of naval forces; that is, armed service is a word with a broader meaning than naval forces:

naval forces: an organization of military vessels belonging to a country and available for sea warfare
armed service: a force that is a branch of the armed forces

Other hypernyms of naval forces include military service, service.

naval forces (noun)	armed service (noun)
an organization of military vessels belonging to a country and available for sea warfare	a force that is a branch of the armed forces