sea wrack vs grass wrack

sea wrack and grass wrack both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea wrack	Yes	No	No	No
grass wrack	Yes	No	No	No

As nouns, sea wrack and grass wrack are synonyms defined as:

sea wrack and grass wrack: submerged marine plant with very long narrow leaves found in abundance along North Atlantic coasts

Other synonyms of sea wrack include eelgrass, Zostera marina.

sea wrack (noun)	grass wrack (noun)
growth of marine vegetation especially of the large forms such as rockweeds and kelp	submerged marine plant with very long narrow leaves found in abundance along North Atlantic coasts
submerged marine plant with very long narrow leaves found in abundance along North Atlantic coasts