- noun a plant with a sour juice sometimes eaten as a salad. Varieties include the sheep sorrel and the wood sorrel.
- A hardy perennial plant, Rumex acetosa, with pointed oval, sour leaves used in salads, soups, etc., cooked with fish or used as a spinach-like vegetable. The variety grown in France is less acid than that which grows wild in the UK. The leaves may be blanched before final cooking to reduce the acidity.