sea wrack

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Seaweed that has been cast ashore.

from the GNU version of the Collaborative International Dictionary of English.

• (Bot.) See wrack.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

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