polar region vs polar zone

polar region and polar zone both are nouns.

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

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

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

Other synonyms of polar region include Frigid Zone.

polar region (noun)	polar zone (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