oarweedEnglishOxford New American Dictionaryoarweed /ˈôrwēd, ˈɔrwid / ▸ noun a large brown kelp with a long hard stalk and a large oar-shaped frond divided into ribbon-like strips, growing on rocky shores. Also called tangle2. Genus Laminaria, class Phaeophyceae, in particular L. digitata.