celery, biennial plant ( Apium graveolens ) of the family Umbelliferae (parsley family), of wide distribution in the wild state throughout the north temperate Old World and much cultivated also in America. It was first cultivated as a medicinal, then (during the Middle Ages) as a flavoring, and finally as a food, chiefly for soups and salads. The seeds are still used for seasoning. Celeriac is a variety cultivated chiefly in N Europe for the large edible turniplike root. Celery is classified in the division Magnoliophyta, class Magnoliopsida, order Umbellales, family Umbelliferae.