Sequoiadendron giganteum vs giant sequoia

Sequoiadendron giganteum and giant sequoia both are nouns.

Word	Noun	Adjective	Verb	Adverb
Sequoiadendron giganteum	Yes	No	No	No
giant sequoia	Yes	No	No	No

As nouns, Sequoiadendron giganteum and giant sequoia are synonyms defined as:

Sequoiadendron giganteum and giant sequoia: extremely lofty evergreen of southern end of western foothills of Sierra Nevada in California; largest living organism

Other synonyms of Sequoiadendron giganteum include big tree, Sequoia gigantea, Sequoia Wellingtonia, Sierra redwood.

Sequoiadendron giganteum (noun)	giant sequoia (noun)
extremely lofty evergreen of southern end of western foothills of Sierra Nevada in California; largest living organism	extremely lofty evergreen of southern end of western foothills of Sierra Nevada in California; largest living organism