What does flank mean?
Flank is both noun and verb, rooted in the language of bodies and battles. As a noun, it names the side of a person or animal between the ribs and the hip, and by extension the side of almost anything — a mountain, a building, or, most famously, an army formation. As a verb, it means to guard, attack, or simply stand at the side of something: 'the house was flanked by two cypress trees.' Its military sense carries particular weight, since flanks are traditionally the vulnerable edges of a force, making 'turning a flank' shorthand for a decisive tactical maneuver. Beyond the battlefield, the word appears in anatomy ('flank pain' often signals kidney trouble) and even on menus, where flank steak is a familiar cut from the cow's abdominal region. Borrowed from French flanc in the early seventeenth century, flank remains a versatile term for sides, edges, and strategic positioning.
The part of a person's or animal's body on either side, between the ribs and the hip.
"The rider pressed his heels against the horse's flank."
In medical contexts, flank pain on one side often points to the kidneys.
The side or edge of an object, structure, or area; especially the right or left side of a military formation.
"They climbed the eastern flank of the mountain."
To position oneself or something at the side of another thing, or to guard or attack its side.
"Two stone lions flanked the entrance to the embassy."
Commonly used passively in description: 'a garden flanked by hedges.'
Pluralizes normally when referring to both sides of a body, object, or formation; in military use, 'flanks' commonly denotes the right and left sides together.
"The regiment protected both of its flanks with artillery."
In military strategy, an army's flanks are its weak points — which is why 'turning a flank' has decided some of history's greatest battles.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of flank
Flank entered English in the early seventeenth century, borrowed from the French word 'flanc', which itself derived from Old French and ultimately traces back to Germanic origins, likely Frankish. The same source gave Spanish its 'flanco', showing how widely the Romance languages adopted the term. Its military vocabulary — including derivatives such as 'flanker' and the maneuver 'to turn a flank' — grew naturally from its original anatomical meaning as armies described the vulnerable sides of their formations.
Related word forms
How flank is actually used
As a verb, 'flank' is often used intransitively in phrases like 'flanked by two towers' — meaning positioned on either side of — a common construction in architectural and photographic description. In anatomy and medicine, 'flank pain' typically refers to discomfort in the side near the kidneys.
Easily confused with flank
'Frank' means honest and direct in expression, while 'flank' refers to a side of a body, object, or formation.