<p><strong>Noun</strong></p><ul><li>Any small tree or spiny shrub of the genus <em>Citrus</em>, of the rue family, including the lemon, lime, orange, tangerine, grapefruit, citron, kumquat, and shaddock, widely cultivated for fruit or grown as an ornamental.</li><li>The tart-to-sweet, pulpy fruit of any of these trees or shrubs, having a characteristically smooth, shiny, stippled skin.</li></ul><p><strong>Adjective</strong></p><ul><li>Also citrous.</li><li>Of or relating to such trees or shrubs, or their fruit.</li></ul>