flank

American  

[flangk] / flæŋk /

noun

1. the side of an animal or a person between the ribs and hip.

2. the thin piece of flesh constituting this part.

3. a slice of meat from the flank of an animal.

4. the side of anything, as of a building.

5. Military, Navy. the extreme right or left side of an army or fleet, or a subdivision of an army or fleet.

6. Fortification.

   1. the right or left side of a work or fortification.

   2. the part of a bastion that extends from the curtain to the face and protects the curtain and the opposite face.

7. Machinery. (on a screw thread or the like) either of the two vertical inclined surfaces between the crest and the root.

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verb (used with object)

1. to stand or be placed or posted at the flank or side of.

   Synonyms:

   border, skirt, edge, line

2. to defend or guard at the flank.

3. Military. to menace or attack the flank of.

4. to pass around or turn the flank of.

verb (used without object)

1. to occupy a position at the flank or side.

2. to present the flank or side.

flank British  

/ flæŋk /

noun

1. the side of a man or animal between the ribs and the hip

2. (loosely) the outer part of the human thigh

3. a cut of beef from the flank

4. the side of anything, such as a mountain or building

5. the side of a naval or military formation

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verb

1. to be located at the side of (an object, building, etc)

2. military to position or guard on or beside the flank of (a formation, etc)

3. military to move past or go round (a flank)

Usage

What is a basic definition of flank? A flank is space between the lowest rib and hip of an animal or person. To flank something means to stand at the side of something. In the military, a flank is a left or right side of an army or fleet of ships. Flank has several other senses as a noun and a verb.The space on your torso between your lowest rib and your hip is called your flank. Animals like cows and horses also have sides referred to as flanks. If a slice of meat comes from this part of an animal’s body, it is a flank cut or flank steak.

• Used in a sentence: The tree branch poked me in my left flank. 

More generally, a flank is the side of anything.

• Used in a sentence: The ball bounced off the left flank of the house. 

In this sense, flank is used to mean to stand or be located at the side of something. A person or thing that flanks something is called a flanker.

• Used in a sentence: Orange trees flanked both sides of the river.

Flank is used in a military sense to refer to the sides of an army. For example, if an army was lined up in rows of soldiers, the soldiers on either end of the rows would make up the army’s flank. An army’s flank is described with directional terms, such as left or right, or compass directions, that is, north, south, east, or west.

• Used in a sentence: The left flank collapsed under the intense arrow fire. 

Flank is used in a similar sense as a verb to mean to attack or harass an army’s flank.

• Used in a sentence: The Roman soldiers charged out of the woods and managed to flank the Greek army. 

Other Word Forms

• unflank verb (used with object)
• well-flanked adjective

Etymology

Origin of flank

before 1100; Middle English; late Old English flanc < Old French < Frankish; compare Old High German hlanca loin

Example Sentences

Japan is fortifying its southwestern flank and developing advanced weapons, with public support for increased defense.

From The Wall Street Journal • Mar. 28, 2026

Another deep area of low pressure will pass to the south of Iceland with strong winds on its southern flank across the UK.

From BBC • Mar. 10, 2026

The audience roars as Keller and Knight flank Storrie before Knight jokes, “It was gonna be just us, but we thought we’d invite the guys too.”

From Salon • Mar. 6, 2026

That has allowed the U.S. to establish “localized air superiority across the southern flank of the Iranian coast and penetrate their defenses with overwhelming precision and firepower,” Caine said.

From Los Angeles Times • Mar. 4, 2026

The Dumpster’s metal flank felt cool and crusty against his bare back.

From "Wringer" by Jerry Spinelli