Mount Tacoma vs Mt. Rainier

Mount Tacoma and Mt. Rainier both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mount Tacoma	Yes	No	No	No
Mt. Rainier	Yes	No	No	No

As nouns, Mount Tacoma and Mt. Rainier are synonyms defined as:

Mount Tacoma and Mt. Rainier: a mountain peak in central Washington; highest peak in the Cascade Range; (14,410 feet high)

Other synonyms of Mount Tacoma include Mount Rainier, Rainier.

Mount Tacoma (noun)	Mt. Rainier (noun)
a mountain peak in central Washington; highest peak in the Cascade Range; (14,410 feet high)	a mountain peak in central Washington; highest peak in the Cascade Range; (14,410 feet high)