keel

¹ American  

[keel] / kil /

noun

1. 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.

2. Literary. a ship or boat.

3. a part corresponding to a ship's keel in some other structure, as in a dirigible balloon.

4. Astronomy. Keel, the constellation Carina.

5. Botany, Zoology. a longitudinal ridge, as on a leaf or bone; a carina.

6. Also called brace molding.  Architecture. a projecting molding the profile of which consists of two ogees symmetrically disposed about an arris or fillet.

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verb (used with or without object)

1. to turn or upset so as to bring the wrong side or part uppermost.

verb phrase

1. keel over

   1. to capsize or overturn.

   2. to fall as in a faint.

      Several cadets keeled over from the heat during the parade.

idioms

1. on an even keel, in a state of balance; steady; steadily.

   The affairs of state are seldom on an even keel for long.

keel ² American  

[keel] / kil /

noun

British Dialect.

1. keelboat.

2. the amount of coal carried by one keelboat.

3. a measure of coal equivalent to 21 long tons and 4 hundredweight (21.5 metric tons).

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keel ³ American  

[keel] / kil /

verb (used with object)

British Dialect.

1. to cool, especially by stirring.

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keel ⁴ American  

[keel] / kil /

noun

1. a red ocher stain used for marking sheep, lumber, etc.; ruddle.

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keel ¹ British  

/ kiːl /

noun

1. one of the main longitudinal structural members of a vessel to which the frames are fastened and that may extend into the water to provide lateral stability

2. well-balanced; steady

3. any structure corresponding to or resembling the keel of a ship, such as the central member along the bottom of an aircraft fuselage

4. biology a ridgelike part; carina

5. a poetic word for ship

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verb

1. to capsize

keel ² British  

/ kiːl /

noun

1. a flat-bottomed vessel, esp one used for carrying coal

2. a measure of coal equal to about 21 tons

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keel ³ British  

/ kiːl /

noun

1. red ochre stain used for marking sheep, timber, etc

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verb

1. to mark with this stain

keel ⁴ British  

/ kiːl /

verb

1. an archaic word for cool

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keel ⁵ British  

/ kiːl /

noun

1. a fatal disease of young ducks, characterized by intestinal bleeding caused by Salmonella bacteria

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keel More Idioms  

More idioms and phrases containing keel

• on an even keel

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Other Word Forms

• keel-less adjective
• keeled adjective

Etymology

Origin of keel¹

First recorded in 1325–75; 1895–1900 keel ¹ for def. 8; Middle English kele, from Old Norse kjǫlr; cognate with Old English cēol “keel, ship”; keel ²

Origin of keel²

First recorded in 1375–1425; late Middle English kele, from Middle Dutch kiel “ship”; cognate with Old English cēol “ship,” German kiel “ship” (obsolete); see keel ¹

Origin of keel³

First recorded before 900; Middle English kelen, Old English cēlan “to be cool”; akin to cool

Origin of keel⁴

First recorded in 1475–85; earlier keyle (north and Scots dialect); compare Scots Gaelic cìl (itself perhaps from English )

Explanation

The keel of a boat is the beam that runs the length of the hull — the body of the boat — and can extend vertically into the water to provide stability. A keel doesn't just refer to the stabilization of boats. When you're on "an even keel," you're stable and steady. On a bird, the keel (or breastbone) enables a bird to fly. On the other hand, if you keel over, you're quite the opposite, since you've just gone crashing to the floor.

Example Sentences

He points out that energy stocks have “virtually retraced their wartime gains,” and adds that “even the bond market is back on an even keel after yesterday’s rally.”

From Barron's • Apr. 15, 2026

After decades of "boom and bust", cross-border retail in Newry and Dundalk is on "an even keel", according to business leaders in the area.

From BBC • Dec. 21, 2025

It’s the humidity, which has spiked to over 80%, that has them feeling ready to keel over between sets.

From The Wall Street Journal • Oct. 10, 2025

You’re very even keel on the surface, so the fact that you say that is also kind of surprising.

From Los Angeles Times • Aug. 21, 2025

“For cryin’ out loud, you weakling, it’s not like you’re gonna keel over and die right here on the spot.”

From "Red Kayak" by Priscilla Cummings