| Seaweed 1. (n.) Popularly, any plant or plants growing in the sea. 2. (n.) Any marine plant of the class Algae, as kelp, dulse, Fucus, Ulva, etc. Thesaurus Entries algae, autophyte, bean, bracken, brown algae, climber, conferva, confervoid, creeper, diatom, fern, fruits and vegetables, fucus, fungus, grapevine, green algae, gulfweed, herb, heterophyte, ivy, kelp, legume, lentil, liana, lichen, liverwort, mold, moss, mushroom, parasite, parasitic plant, pea, perthophyte, phytoplankton, planktonic algae, plant families, puffball, pulse, red algae, rockweed, rust, saprophyte, sargasso, sargassum, sea lentil, sea moss, sea wrack, smut, succulent, toadstool, vetch, vine, wort, wrack |