sea holm vs shrub

sea holm and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea holm	Yes	No	No	No
shrub	Yes	No	No	No

As nouns, shrub is a hypernym of sea holm; that is, shrub is a word with a broader meaning than sea holm:

sea holm: European evergreen eryngo with twisted spiny leaves naturalized on United States east coast; roots formerly used as an aphrodisiac
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of sea holm include bush.

sea holm (noun)	shrub (noun)
European evergreen eryngo with twisted spiny leaves naturalized on United States east coast; roots formerly used as an aphrodisiac	a low woody perennial plant usually having several major stems