Himalayas vs Himalaya Mountains

Himalayas and Himalaya Mountains both are nouns.

Word	Noun	Adjective	Verb	Adverb
Himalayas	Yes	No	No	No
Himalaya Mountains	Yes	No	No	No

As nouns, Himalayas and Himalaya Mountains are synonyms defined as:

Himalayas and Himalaya Mountains: a mountain range extending 1500 miles on the border between India and Tibet; this range contains the world's highest mountain

Other synonyms of Himalayas include Himalaya.

Himalayas (noun)	Himalaya Mountains (noun)
a mountain range extending 1500 miles on the border between India and Tibet; this range contains the world's highest mountain	a mountain range extending 1500 miles on the border between India and Tibet; this range contains the world's highest mountain