#arch  (architecture) a masonry construction (usually curved) for spanning an opening and supporting the weight above it
  supertype:  physical_structure__structure__construction  a thing constructed; a complex construction or entity; "the structure consisted of a series of arches"; "she wore her hair in an amazing construction of whirls and ribbons"
  part:  keystone  springer  voussoir
  part of:  aqueduct  arcade.structure  bridge
  subtype:  abutment_arch  an arch supported by an abutment
  subtype:  broken_arch  an arch with a gap at the apex; the gap is usually filled with some decoration
  subtype:  camber_arch  an arch with a straight horizontal extrados and a slightly arched intrados
  subtype:  corbel_arch  (architecture) an arch constructed of masonry courses that are corbelled until they meet
  subtype:  flat_arch__straight_arch  an arch with mutually supporting voussoirs that has a straight horizontal extrados and intrados
  subtype:  pier_arch  an arch supported on piers
  subtype:  pointed_arch__pointedarch  an arch with a pointed apex
     subtype:  drop_arch  a blunt pointed arch drawn from two centers within the span
     subtype:  Gothic_arch  a pointed arch; usually has a joint (instead of a keystone) at the apex
        subtype:  lancet_arch__lancet  an acutely pointed Gothic arch, like a lance
     subtype:  ogee_arch__keel_arch  a pointed arch having an S-shape on both sides
     subtype:  trefoil_arch__trefoilarch  a pointed arch having cusps in the intrados on either side of the apex
  subtype:  proscenium_arch  the arch over the opening in the proscenium wall
  subtype:  rampant_arch__rampantarch  an arch whose support is higher on one side than on the other
  subtype:  round_arch__roundarch  an arch formed in a continuous curve
     subtype:  bell_arch  a round arch resting on corbels
     subtype:  Moorish_arch__horseshoe_arch__horseshoearch  a round arch that widens before rounding off
     subtype:  Roman_arch__semicircular_arch  a round arch drawn from a single center
     subtype:  three-centered_arch__basket-handle_arch  a round arch whose inner curve is drawn with circles having three centers
  subtype:  rowlock_arch__rowlockarch  an arch that is formed with more than one concentric row of voussoirs
  subtype:  safety_arch  an undecorated arch that is included in order to strengthen or support a construction
  subtype:  scoinson_arch__sconcheon_arch__sconcheonarch  an arch that supports part of the wall
  subtype:  shouldered_arch  an arch consisting of a horizontal lintel supported at each end by corbels that project into the aperture
  subtype:  skeen_arch__skeenarch__skene_arch__skenearch__schemearch__diminished_arch  a arch whose height is less than half its width
  subtype:  skew_arch  an arch whose jambs are not at right angles with the face
  subtype:  squinch  a small arch built across the interior angle of two walls (usually to support a spire)
     subtype:  trumpet_arch__trumpetarch  a conical squinch
  subtype:  trimmer_arch__trimmerarch  an arch built between trimmers in a floor (to support the weight of a hearth)
  subtype:  triumphal_arch__triumphalarch  a monumental archway; usually they are built to commemorate some notable victory
  subtype:  Tudor_arch__four-centered_arch  a low elliptical or pointed arch; usually drawn from four centers

No statement uses or specializes arch; click here to add one.