savoy vs head cabbage

savoy and head cabbage both are nouns.

Word	Noun	Adjective	Verb	Adverb
savoy	Yes	No	No	No
head cabbage	Yes	No	No	No

As nouns, head cabbage is a hypernym of savoy; that is, head cabbage is a word with a broader meaning than savoy:

savoy: head of soft crinkly leaves
head cabbage: any of several varieties of cabbage having a large compact globular head; may be steamed or boiled or stir-fried or used raw in coleslaw

savoy (noun)	head cabbage (noun)
head of soft crinkly leaves	any of several varieties of cabbage having a large compact globular head; may be steamed or boiled or stir-fried or used raw in coleslaw
	any of various cultivated cabbage plants having a short thick stalk and large compact head of edible usually green leaves