American arborvitae vs white cedar

American arborvitae and white cedar both are nouns.

Word	Noun	Adjective	Verb	Adverb
American arborvitae	Yes	No	No	No
white cedar	Yes	No	No	No

As nouns, American arborvitae and white cedar are synonyms defined as:

American arborvitae and white cedar: small evergreen of eastern North America having tiny scalelike leaves on flattened branchlets

Other synonyms of American arborvitae include northern white cedar, Thuja occidentalis.

American arborvitae (noun)	white cedar (noun)
small evergreen of eastern North America having tiny scalelike leaves on flattened branchlets	slow-growing medium-sized cedar of east coast of the United States; resembles American arborvitae
	small evergreen of eastern North America having tiny scalelike leaves on flattened branchlets