Word Origin & History
"lowest timber of a ship or boat," mid-14c., from O.N. kjölr "keel," from P.Gmc. *keluz, of uncertain origin. Etymologists say this is unconnected with the root of M.Du. kiel "ship," O.E. ceol "ship's prow," O.H.G. kiel, Ger. Kiel "ship," but the two words have influenced each other. This other
word is said to be from P.Gmc. *keula, from PIE *geul- "rounded vessel." Keel still is used locally in England and U.S. for "flat-bottomed boat," especially on the Tyne. To keel over (1876) is from the nautical image of a ship turning keel-up. Keelhaul is 17c. from Du. kielhalen "to haul under the keel," an old punishment. The verb is 1838, Amer.Eng., from the noun.