The Collaborative International Dictionary of English v.0.48:

Concaved \Con"caved\, a. (Her.)
   Bowed in the form of an arch; -- called also arched.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Arch \Arch\, v. t. [imp. & p. p. Arched ([aum]rcht); p. pr. &
   vb. n. Arching.]
   1. To cover with an arch or arches.
      [1913 Webster]

   2. To form or bend into the shape of an arch.
      [1913 Webster]

            The horse arched his neck.            --Charlesworth.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Arched \Arched\, a.
   Made with an arch or curve; covered with an arch; as, an
   arched door.
   [1913 Webster]

WordNet (r) 3.0 (2006):

arched
    adj 1: constructed with or in the form of an arch or arches; "an
           arched passageway"
    2: forming or resembling an arch; "an arched ceiling" [syn:
       arced, arched, arching, arciform, arcuate, bowed]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "arched":
   arciform, arclike, arcual, bandy, bent, bowed, bowlike, concave,
   convex, convexed, curvilinear, embowed, excurvate, excurvated,
   excurved, gibbose, gibbous, humpbacked, humped, humpy, hunched,
   hunchy, out-bowed, oxbow, rotund, round, rounded, vaulted