polar zone vs polar region

polar zone and polar region both are nouns.

Word	Noun	Adjective	Verb	Adverb
polar zone	Yes	No	No	No
polar region	Yes	No	No	No

As nouns, polar zone and polar region are synonyms defined as:

polar zone and polar region: the part of the Earth's surface forming a cap over a pole; characterized by frigid climate

Other synonyms of polar zone include Frigid Zone.

polar zone (noun)	polar region (noun)
the part of the Earth's surface forming a cap over a pole; characterized by frigid climate	the part of the Earth's surface forming a cap over a pole; characterized by frigid climate