citrus

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various evergreen, usually spiny shrubs or trees of the genus Citrus, such as the grapefruit, lemon, or orange, native to southern and southeast Asia, having leathery, aromatic, unifoliolate compound leaves and widely cultivated for their juicy edible fruits that have a leathery aromatic rind.
2. n. The fruit of any of these plants.
3. adj. Of or relating to any of the citrus plants or their fruits.

Century Dictionary and Cyclopedia

1. n. A citron-tree; in general, any tree or fruit of the genus Citrus: as, citrus-culture; the citrus trade.
2. n. [capitalized] A genus of small trees, natural order Rutaceæ, with pinnate but apparently simple coriaceous and punctate leaves upon usually winged petioles. The flowers are white and fragrant, with numerous stamens united by their filaments into several irregular bundles. The fruit is pulpy, with a spongy rind. To this genus belong the orange, C. Aurantium, of which the kumquat is a variety; the shaddock and pumelo, C. decumana; the lemon and citron, C. medica; and the lime, which probably originated from C. Hystrix.

Wiktionary

1. n. Any of several shrubs or trees of the family Rutaceae.
2. n. The fruit of such plants, generally spherical, oblate, or prolate, consisting of an outer glandular skin called zest, an inner white skin, and generally between 8 and 16 sectors filled with pulp consisting of cells with one end attached to the inner skin. Citrus fruits include orange, grapefruit, lemon, lime, and citron.
3. adj. Of, or relating to citrus plants or fruit.

GNU Webster's 1913

1. n. (Bot.) A genus of trees including the orange, lemon, lime, tangerine, citron, grapefruit, etc., originally natives of southern Asia.
2. n. (Bot.) any tree belonging to the genus Citrus, having leathery evergreen leaves and bearing a soft pulpy fruit covered by a thick skin; -- called also citrus tree.
3. n. (Bot.) the fruit of a tree belonging to the genus Citrus, having a thick shiny skin and a soft, sweet to tart pulp.

WordNet 3.0

1. n. any of numerous fruits of the genus Citrus having thick rind and juicy pulp; grown in warm regions
2. n. any of numerous tropical usually thorny evergreen trees of the genus Citrus having leathery evergreen leaves and widely cultivated for their juicy edible fruits having leathery aromatic rinds