Frigid Zone vs polar zone

Frigid Zone and polar zone both are nouns.

Word	Noun	Adjective	Verb	Adverb
Frigid Zone	Yes	No	No	No
polar zone	Yes	No	No	No

As nouns, Frigid Zone and polar zone are synonyms defined as:

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

Other synonyms of Frigid Zone include polar region.

Frigid Zone (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