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.

---

verb (used with object)

flanks, present (3rd person singular) flanked, past participle, past flanking present participle

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)

flanks, present (3rd person singular) flanked, past participle, past flanking present participle

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

---

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

Derived Forms

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

Conjugated Forms

Present

• has flanked
  perfect 3rd person singular
• have flanked
  perfect
• is flanking
  progressive 3rd person singular
• have been flanking
  perfect progressive
• are flanking
  progressive
• has been flanking
  perfect progressive 3rd person singular
• am flanking
  progressive 1st person singular
• flanking
  participle
• flanks
  singular 3rd person

Past

• had flanked
  perfect
• had been flanking
  perfect progressive
• were flanking
  progressive plural
• flanked
  participle
• flanked
  simple
• was flanking
  progressive singular

Future

• will flank
  simple
• will have flanked
  perfect
• will have been flanking
  perfect progressive
• will be flanking
  progressive

Etymology

Origin of flank

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

Explanation

A flank is the side of something, whether of beef or a military formation. Although flank is specifically used to talk about a cut of meat, or the right or left side of a military formation, we also use it in those same senses for other objects or even metaphorically. You might, for example, refer to the more conservative flank of a political party. This word can also be used as a verb. If you see someone walking down the street with bodyguards on either side, she's flanked by guards.

Example Sentences

"There is a common understanding that we need to have better air defence of the eastern flank and not just Romania," she said.

From Barron's • Jun. 3, 2026

With City's midfielders close to each other, Doku - receiving in-field - would turn and drive at the defence, attracting players towards him while freeing up space for Nico O'Reilly on the left flank.

From BBC • May 16, 2026

Fernandes runs down the right flank having left his central position.

From BBC • May 8, 2026

Although it shouldn't take too many guesses to figure out who, on the opposite flank to Facu, Brazilian left-back Roberto Larcos was meant to represent.

From BBC • May 5, 2026

In the fields, nothing moved except the constantly swishing tails of the cows gathered flank to flank in the shade.

From "Watership Down: A Novel" by Richard Adams