military service vs armed service

military service and armed service both are nouns.

Word	Noun	Adjective	Verb	Adverb
military service	Yes	No	No	No
armed service	Yes	No	No	No

As nouns, military service and armed service are synonyms defined as:

military service and armed service: a force that is a branch of the armed forces

Other synonyms of military service include service.

military service (noun)	armed service (noun)
land tenure by service in the lord's army	a force that is a branch of the armed forces
a force that is a branch of the armed forces