Cornus mas vs dogwood

Cornus mas and dogwood both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cornus mas	Yes	No	No	No
dogwood	Yes	No	No	No

As nouns, dogwood is a hypernym of Cornus mas; that is, dogwood is a word with a broader meaning than Cornus mas:

Cornus mas: deciduous European shrub or small tree having bright red fruit
dogwood: a tree of shrub of the genus Cornus often having showy bracts resembling flowers

Other hypernyms of Cornus mas include cornel, dogwood tree.

Cornus mas (noun)	dogwood (noun)
deciduous European shrub or small tree having bright red fruit	a tree of shrub of the genus Cornus often having showy bracts resembling flowers
	hard tough wood of any dogwood of the genus Cornus; resembles boxwood