bastion vs defense force

bastion and defense force both are nouns.

Word	Noun	Adjective	Verb	Adverb
bastion	Yes	No	No	No
defense force	Yes	No	No	No

As nouns, defense force is a hypernym of bastion; that is, defense force is a word with a broader meaning than bastion:

bastion: a group that defends a principle
defense force: an organization of defenders that provides resistance against attack

Other hypernyms of bastion include defence, defence force, defense.

bastion (noun)	defense force (noun)
projecting part of a rampart or other fortification	an organization of defenders that provides resistance against attack
a stronghold into which people could go for shelter during a battle
a group that defends a principle