n. Ascophyllum nodosum, a seaweed also known as kelp.
n. Fucus vesiculosus, a similar seaweed also known as bladderwrack.
the GNU version of the Collaborative International Dictionary of English
n. Any coarse seaweed growing on sea-washed rocks, especially Fucus.
The Century Dictionary and Cyclopedia
n. A seaweed of the genera Fucus, Sargassum, etc., common on the rocks exposed at low tide.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. coarse brown seaweed growing on rocks exposed at low tide
Word Usage
"When gathering your equipment, look for rockweed—it's the best seaweed for clambakes because its seawater-filled pockets burst during cooking and add brininess and moisture to the other ingredients."