flexure

Word family

• flex
  verbB1
• flexible
  adjectiveB1
• flexibility
  nounB1
• flexion
  nounC1
• inflexible
  adjectiveB2

Synonym discussion

Sense: noun/1

While flexure, bend, fold, curve, and flexion all describe some kind of deviation from a straight line, they differ in scope and register. Flexure is the most formal and technical, used predominantly in medicine and geology to name a specific bent area (e.g. splenic flexure). Bend is the everyday equivalent — you bend your arm, a road bends, a pipe bends. Fold implies a sharper, doubled-over crease, like folding paper or a fold in rock strata. Curve is the broadest term for any smooth, rounded line. Flexion is a near-synonym restricted to anatomy: the act of bending a joint (e.g. flexion of the knee), while flexure can also name the resulting bent area itself. A geologist might describe a flexure in a rock layer that was formed by millions of years of pressure; in everyday English, you would simply call that same feature a bend in the rock.

Etymology

Flexure comes from Latin flexura, meaning 'a bending' or 'a turning', which itself derives from flectere ('to bend'). The word entered English in the late 1500s through French and was initially used in general writing before taking on specialised meanings in anatomy and geology during the 1800s.