old woman vs genus Artemisia

old woman and genus Artemisia both are nouns.

Word	Noun	Adjective	Verb	Adverb
old woman	Yes	No	No	No
genus Artemisia	Yes	No	No	No

old woman (noun)	genus Artemisia (noun)
a woman who is old	usually aromatic shrubs or herbs of north temperate regions and South Africa and western South America: wormwood, sagebrush, mugwort, tarragon
herb with greyish leaves found along the east coast of North America; used as an ornamental plant