lime1 / līm/ • n. (also quick·lime) a white caustic alkaline substance consisting of calcium oxide, obtained by heating limestone. ∎ (also slaked lime) a white alkaline substance consisting of calcium hydroxide, made by adding water to quicklime. ∎ (in general use) any of a number of calcium compounds, esp. calcium hydroxide, used as an additive to soil or water. ∎ archaic birdlime. • v. [tr.] 1. treat (soil or water) with lime to reduce acidity and improve fertility or oxygen levels. ∎ [often as adj.] (limed) give (wood) a bleached appearance by treating it with lime: limed oak dining furniture. 2. archaic catch (a bird) with birdlime. DERIVATIVES: lim·y / ˈlīmē/ adj. (lim·i·er , lim·i·est ) . lime2 • n. 1. a rounded citrus fruit similar to a lemon but greener, smaller, and with a distinctive acid flavor. 2. (also lime tree) the evergreen citrus tree (Citrus aurantifolia) that produces this fruit, widely cultivated in warm climates. 3. a bright light green color like that of a lime. lime3 (also lime tree) • n. another term for linden, esp. the European linden.