'CAO' definitions:

Definition of 'CaO'

From: GCIDE

Lime \Lime\, n. [AS. l[imac]m; akin to D. lijm, G. leim, OHG. l[imac]m, Icel. l[imac]m, Sw. lim, Dan. liim, L. limus mud, linere to smear, and E. loam. [root]126. Cf. Loam, Liniment.]
1. Birdlime. [1913 Webster]
Like the lime That foolish birds are caught with. --Wordsworth. [1913 Webster]
2. (Chem.) Oxide of calcium, CaO; the white or gray, caustic substance, usually called quicklime, obtained by calcining limestone or shells, the heat driving off carbon dioxide and leaving lime. It develops great heat when treated with water, forming slaked lime, and is an essential ingredient of cement, plastering, mortar, etc. [1913 Webster +PJC]
Note: Lime is the principal constituent of limestone, marble, chalk, bones, shells, etc. [1913 Webster]
Caustic lime, Calcium hydroxide or slaked lime; also, in a less technical sense, calcium oxide or quicklime.
Lime burner, one who burns limestone, shells, etc., to make lime.
Lime pit, a limestone quarry.
Lime rod, Lime twig, a twig smeared with birdlime; hence, that which catches; a snare. --Chaucer. [1913 Webster]