moat

American  

[moht] / moʊt /

noun

1. a deep, wide trench, usually filled with water, surrounding the rampart of a fortified place, such as a town or a castle.

2. any trench, such as one used for confining animals in a zoo.

3. a competitive advantage a business has in its field.

   The company's moat was reduced when the patent on the devices they sold expired.

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moat British  

/ məʊt /

noun

1. a wide water-filled ditch surrounding a fortified place, such as a castle

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verb

1. (tr) to surround with or as if with a moat

   a moated grange

Etymology

Origin of moat

First recorded in 1325–75; Middle English mote, from Old French: “clod, mound,” of obscure origin

Explanation

Not many houses these days have a moat — it's a trench dug outside a castle and is usually full of water. A moat means "Keep out!" You're most likely to hear about moats if you read a fairy tale or a history of medieval times. This water-filled ditch is one of the lines of defense for a castle. In the old days, it was pretty effective. If you filled the moat with a deadly fish — like a piranha — that was an even better defense. A moat is pretty much the opposite of a welcome mat.

Example Sentences

The project is also aimed at establishing a wider moat around XTX’s business as rivals pursue their own AI-based strategies.

From The Wall Street Journal • Apr. 23, 2026

“Not that many companies out there that have this kind of moat, which is a global wallet that everyone recognizes.”

From Los Angeles Times • Apr. 3, 2026

"It's got no moat but it has got a little railway I can drive around," he said.

From BBC • Mar. 28, 2026

After the quake, thousands of people whose homes had been made uninhabitable or who feared aftershocks slept out for weeks by the moat, but it is once again the preserve of morning joggers and sightseers.

From Barron's • Mar. 26, 2026

He looked down at Jojo vanishing into the moat, and he went back to Jojo.

From "My Life with the Chimpanzees" by Jane Goodall

Related Words

• gully
• trench