n. An umbelliferous plant, Apium graveolens, a native of Europe, and long cultivated in gardens for the use of the table.n. See Vallisneria.n. On the Pacific coast, an aquatic umbelliferous plant, Œnanthe sarmentosa, the stems of which have the taste of celery and were eaten by the Indians. The poisonous Oregon water-hemlock is said to be sometimes mistaken for this.