The Collaborative International Dictionary of English v.0.48:
Arciform \Ar"ci*form\, a. [L. arcus bow + -form.] Having the form of an arch; curved. [1913 Webster]WordNet (r) 3.0 (2006):
arciform adj 1: forming or resembling an arch; "an arched ceiling" [syn: arced, arched, arching, arciform, arcuate, bowed]