boot camp vs cantonment

boot camp and cantonment both are nouns.

Word	Noun	Adjective	Verb	Adverb
boot camp	Yes	No	No	No
cantonment	Yes	No	No	No

As nouns, cantonment is a hypernym of boot camp; that is, cantonment is a word with a broader meaning than boot camp:

boot camp: camp for training military recruits
cantonment: temporary living quarters specially built by the army for soldiers

Other hypernyms of boot camp include bivouac, camp, encampment.

boot camp (noun)	cantonment (noun)
camp for training military recruits	temporary living quarters specially built by the army for soldiers