Celeriac, Apium graveolens var rapaceum (also known as 'turnip-rooted celery' or 'knob celery'), is a specially-adapted variety of celery, which is grown for its large and well-developed root rather than for the stem and leaves. The root is used when it is about 100 mm or the size a medium-sized potato. Celeriac may be used raw or fresh. It is best to peel celeriac before use, since the outer skin is tough and stringy. It has the celery flavor, so it is often used as a flavoring in soups and stews; it can also be mashed or used in casseroles and baked dishes.

Celeriac has good keeping properties, and should last 3 to 4 months if stored between 0° and 5 °C and not allowed to dry out.