angelica vs archangel

angelica and archangel both are nouns.

Word	Noun	Adjective	Verb	Adverb
angelica	Yes	No	No	No
archangel	Yes	No	No	No

As nouns, archangel is a hyponym of angelica; that is, archangel is a word with a more specific, narrower meaning than angelica:

angelica: any of various tall and stout herbs of the genus Angelica having pinnately compound leaves and small white or greenish flowers in compound umbels
archangel: a biennial cultivated herb; its stems are candied and eaten and its roots are used medicinally

Other hyponyms of angelica include Angelica Archangelica, garden angelica, Angelica sylvestris, wild angelica.

angelica (noun)	archangel (noun)
aromatic stems or leaves or roots of Angelica Archangelica	an angel ranked above the highest rank in the celestial hierarchy
candied stalks of the angelica plant	a biennial cultivated herb; its stems are candied and eaten and its roots are used medicinally
any of various tall and stout herbs of the genus Angelica having pinnately compound leaves and small white or greenish flowers in compound umbels