<p><strong>noun</strong></p><ul><li>Nautical. a central fore-and-aft structural member in the bottom of a hull, extending from the stem to the sternpost and having the floors or frames attached to it, usually at right angles: sometimes projecting from the bottom of the hull to provide stability.</li><li>Literary. a ship or boat.</li><li>a part corresponding to a ship's keel in some other structure, as in a dirigible balloon.</li><li>Keel, Astronomy. the constellation Carina.</li><li>Botany, Zoology. a longitudinal ridge, as on a leaf or bone; a carina.</li><li>Also called brace molding.</li><li>Architecture. a projecting molding the profile of which consists of two ogees symmetrically disposed about an arris or fillet.</li></ul><p><strong>verb</strong></p><ul><li>(used with or without object) to turn or upset so as to bring the wrong side or part uppermost.</li><li>verb phrase to capsize or overturn.</li><li>to fall as in a faint: Several cadets keeled over from the heat during the parade.</li></ul>