Source : Webster's Revised Unabridged Dictionary (1913)

Arc \Arc\ ([aum]rk), v. i. [imp. & p. p. {Arcked} ([aum]rkt); p.
   pr. & vb. n. {Arcking}.] (Elec.)
   To form a voltaic arc, as an electrical current in a broken
   or disconnected circuit.

Source : WordNet®

arc
     n 1: electrical conduction through a gas in an applied electric
          field [syn: {discharge}, {spark}, {electric arc}, {electric
          discharge}]
     2: a continuous portion of a circle
     3: something curved in shape [syn: {bow}]
     [also: {arcking}, {arcked}]

arc
     v : form an arch or curve; "her back arches"; "her hips curve
         nicely" [syn: {arch}, {curve}]
     [also: {arcking}, {arcked}]

arcked
     See {arc}