army tank vs armoured combat vehicle

army tank and armoured combat vehicle both are nouns.

Word	Noun	Adjective	Verb	Adverb
army tank	Yes	No	No	No
armoured combat vehicle	Yes	No	No	No

As nouns, army tank and armoured combat vehicle are synonyms defined as:

army tank and armoured combat vehicle: an enclosed armored military vehicle; has a cannon and moves on caterpillar treads

Other synonyms of army tank include armored combat vehicle, tank.

army tank (noun)	armoured combat vehicle (noun)
an enclosed armored military vehicle; has a cannon and moves on caterpillar treads	an enclosed armored military vehicle; has a cannon and moves on caterpillar treads