fissure

American  

[fish-er] / ˈfɪʃ ər /

noun

1. a narrow opening produced by cleavage or separation of parts.

2. cleavage.

3. Anatomy. a natural division or groove in an organ, as in the brain.

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verb (used with object)

fissured, fissuring

1. to make fissures in; cleave; split.

verb (used without object)

fissured, fissuring

1. to open in fissures; become split.

fissure British  

/ ˈfɪʃə /

noun

1. any long narrow cleft or crack, esp in a rock

2. a weakness or flaw indicating impending disruption or discord

   fissures in a decaying empire

3. anatomy a narrow split or groove that divides an organ such as the brain, lung, or liver into lobes See also sulcus

4. a small unnatural crack in the skin or mucous membrane, as between the toes or at the anus

5. a minute crack in the surface of a tooth, caused by imperfect joining of enamel during development

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verb

1. to crack or split apart

fissure Scientific  

/ fĭsh′ər /

1. A long, narrow crack or opening in the face of a rock. Fissures are often filled with minerals of a different type from those in the surrounding rock.

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Other Word Forms

• fissural
  adjective
• fissureless
  adjective
• subfissure
  noun
• superfissure
  noun

Etymology

Origin of fissure

1375–1425; late Middle English < Latin fissūra cleaving, cleft, fissure, equivalent to fiss ( us ) divided ( see fissi-) + -ūra -ure

Explanation

A long fine crack in the surface of something is called a fissure. If you see a fissure in the ice on a frozen lake, you'll want to take off your skates and head back to the car. Fissure has its roots in the Latin word fissura, meaning a cleft or crack. If something breaks into fine cracks, you can describe the action with the verb form of fissure. For example, "She watched in horror as the earth fissured beneath her feet, recognizing the signs of an earthquake but powerless to do anything to save herself except throw herself to the ground and hang on."

Example Sentences

The platinum spike may have come from a volcanic fissure eruption in Iceland rather than an object from space.

From Science Daily • Mar. 20, 2026

Perhaps the fissure should bring to mind Nordic depression, or familial misadventures in communication.

From The Wall Street Journal • Nov. 6, 2025

Like the fissure between Tim and Millie, the cracks in our once-perfect relationship formed so gradually I didn’t even notice them.

From Salon • Jul. 30, 2025

However, there has been little concern to aviation as these recent eruptions are mostly small fissure eruptions with large and slow lava flows - rather than the explosive ash eruption from Eyjafjallajökull.

From BBC • Apr. 15, 2025

The fissure split and grew, like those scenes in disaster movies when an earthquake cracks the streets apart and chases the hero.

From "Tristan Strong Punches a Hole in the Sky" by Kwame Mbalia

Related Words

• cleavage
• crevice