General English


  • A curved or flat structure spanning an opening. The shape and size of arches are limited by the materials used and the support provided.


  • noun a curved part of the body, especially under the foot
  • prefix
    (written as arch-)
    chief, most important

Real Estate

  • noun a curved structure that forms the upper edge of an open space such as a window, a doorway or the space between a bridge’s supports
  • verb to build something in the shape of an arch or with arch-shaped supports


  • noun any of the several curved arrangements of bones and ligaments that form the foot, especially the medial arch on the inside of the foot


  • acronym forAutoregressive Conditional Heteroskedasticity
    (written as ARCH)

Origin & History of “arch”

English acquired arch via Old French arche and a hypothetical vulgar Latin *arca from Latin arcus ‘curve, arch, bow’ (from which English also got arc (14th c.)). when it first came into the language it was still used in the general sense of ‘curve, arc’ as well as ‘curved structure’ (Chaucer in his Treatise on the astrolabe 1391 wrote of ‘the arch of the day … from the sun arising till it go to rest’), but this had died out by the mid 19th century. Vulgar Latin *arca also produced Italian arcata, which entered English via French as arcade in the 18th century.

Arch meaning ‘saucy’ is an adjectival use of the prefix arch- (as in archetype).