laminarian UK /ˌlæm.ɪˈnɛə.ɹi.ən/US /ˌlæ.məˈnɛ.ɹi.ən/adjective 1noun 1forms 1 adjective1 •Relating to seaweeds of the genus Laminaria, or to the depth zone of the sea in which they grow. noun1 •Any seaweed of the genus Laminaria. formslaminarians