citron, name for a tree (Citrus medica) of the family Rutaceae (orange family), and for its fruit, the earliest of the citrus fruits to be introduced to Europe from Asia. The small evergreen tree is now cultivated commercially in the Mediterranean region and, to a lesser extent, in the West Indies, Florida, and California. The large fruit has a rough and furrowed surface and a thin outer rind of yellowish green color. The inner rind is thick, white, and tender, and the pulp is small and acid. The juice is sometimes used as a beverage or syrup. The rind, candied and preserved, is used in confectionery and cookery. The fruit, also known as etrog or ethrog, is used in the celebration of the Jewish Feast of Tabernacles, or Sukkoth. The name citron is also applied to a small species of watermelon with a thick rind, used to make preserves. Citron is classified in the division Magnoliophyta, class Magnoliopsida, order Sapindales, family Rutaceae.

Small evergreen tree or shrub (Citrus medica). A member of the rue family, citron is cultivated in Mediterranean countries and the West Indies. It has irregular, spreading, spiny branches and large, pale green, broadly oblong leaves. The flowers of the acidic varieties (e.g., the Diamante) are purple on the outside and white on the inside; those of sweet varieties (e.g., the Corsican) are creamy white. The oval or oblong fruit yields firm pulp, either acidic or sweet, that is used only for by-products. The thick peel is cured in brine, candied, and sold as a confection. The fruit of the Etrog variety is used in Jewish religious rites.

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