canker

American  

[kang-ker] / ˈkæŋ kər /

noun

1. a gangrenous or ulcerous sore, especially in the mouth.

2. a disease affecting horses' feet, usually the soles, characterized by a foul-smelling exudate.

3. a defined area of diseased tissue, especially in woody stems.

4. something that corrodes, corrupts, destroys, or irritates.

   Synonyms:

   scourge, cancer, blight

5. Also called canker rose.  British Dialect. dog rose.

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verb (used with object)

1. to infect with canker.

2. to corrupt; destroy slowly.

verb (used without object)

1. to become infected with or as if with canker.

canker British  

/ ˈkæŋkə /

noun

1. an ulceration, esp of the lips or lining of the oral cavity

2. vet science

   1. a disease of horses in which the horn of the hoofs becomes soft and spongy

   2. an inflammation of the lining of the external ear, esp in dogs and cats, resulting in a discharge and sometimes ulceration

   3. ulceration or abscess of the mouth, eyelids, ears, or cloaca of birds

3. an open wound in the stem of a tree or shrub, caused by injury or parasites

4. something evil that spreads and corrupts

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verb

1. to infect or become infected with or as if with canker

Etymology

Origin of canker

before 1000; Middle English; Old English cancer < Latin cancer; see cancer

Explanation

A canker is a kind of sore. Some people are prone to getting cankers on their mouths. Canker can also refer to anything that is terrible and difficult to get rid of. Your parents might complain that the abandoned, run-down house two blocks away is a canker on your neighborhood. In medicine, cankers are ulcers that are difficult to treat (the word is closely related to cancer). In agriculture, canker refers to a fungal disease that attacks the bark of trees. If one kid in your class misbehaves, and everyone suddenly follows his lead, that kid could be described (by your teachers) as a canker.

Example Sentences

There was citrus canker, a viral infection that had plagued citrus for years prior to the arrival of greening.

From Slate • Apr. 20, 2026

As humans, we are nothing if not fascinated by our own bodies, whether that’s picking a scab, prodding a canker sore or popping a pimple.

From Los Angeles Times • Feb. 21, 2024

“There is a canker that Miss Havisham has allowed, welcomed even, in her heartbreak and desire for revenge.”

From New York Times • Mar. 24, 2023

As instances of this nature may be mentioned English potato scab, silver scurf, chestnut blight disease and citrus canker, specimens of all of which had been secured by correspondence or requests for mycological assistance.

From Scientific American • Jan. 26, 2023

I guess I developed some kind of canker sores in my intestines because of the Merrick’s, and filth leaked out into the rest of my body.

From "Landscape with Invisible Hand" by M.T. Anderson

Related Words

• blight
• corrosion
• scourge