(astronomy) A summer constellation of the southern sky, said to resemble the keel of a ship. It contains the star Canopus, the second brightest star in the night sky. Until 1763, it was part of a larger constellation, Argo Navis.

A longitudinal ridge or projection like the keel of a boat.

(botany) Part of a papilionaceous flower consisting of two petals, commonly united, which encloses the organs of fructification.

(zoology) The keel of the breastbone of birds.

(anatomy) Any of several features that have a projecting central ridge