The Collaborative International Dictionary of English v.0.48:

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.
   [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Arc \Arc\, n. [F. arc, L. arcus bow, arc. See Arch, n.]
   1. (Geom.) A portion of a curved line; as, the arc of a
      circle or of an ellipse.
      [1913 Webster]

   2. A curvature in the shape of a circular arc or an arch; as,
      the colored arc (the rainbow); the arc of Hadley's
      quadrant.
      [1913 Webster]

   3. An arch. [Obs.]
      [1913 Webster]

            Statues and trophies, and triumphal arcs. --Milton.
      [1913 Webster]

   4. The apparent arc described, above or below the horizon, by
      the sun or other celestial body. The diurnal arc is
      described during the daytime, the nocturnal arc during the
      night.
      [1913 Webster]

   Electric arc, Voltaic arc. See under Voltaic.
      [1913 Webster]

WordNet (r) 3.0 (2006):

arc
    n 1: electrical conduction through a gas in an applied electric
         field [syn: discharge, spark, arc, electric arc,
         electric discharge]
    2: a continuous portion of a circle
    3: something curved in shape [syn: bow, arc]
    v 1: form an arch or curve; "her back arches"; "her hips curve
         nicely" [syn: arch, curve, arc]

Moby Thesaurus II by Grady Ward, 1.0:

59 Moby Thesaurus words for "arc":
   AC arc, Poulsen arc, aperiodic discharge, arc column,
   arc discharge, arc light, arch, bend, bow, brush discharge,
   catacaustic, catenary, caustic, circle, color filter, conchoid,
   crook, curl, curvation, curvature, curve, diacaustic, dimmer,
   discharge, disruptive discharge, electric discharge,
   electric shock, electric spark, electrodeless discharge, ellipse,
   festoon, floats, flood, floodlight, footlights, foots,
   galvanic shock, gelatin, glow discharge, hook, hyperbola,
   klieg light, light plot, lights, limelight, lituus, marquee,
   medium, oscillatory discharge, parabola, round, shock,
   silent discharge, sinus, spark, spark gap, spot, spotlight,
   tracery



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

ARC
       Advanced RISC Computing [architecture] (ACE, RISC)


The Free On-line Dictionary of Computing (30 December 2018):

arc

   1.  An old archive format for IBM PC.
   The format is now so obscure that it is only likely to be
   supported by jack-of-all-trades decompression programs such as
   WINZIP.

   2.  An edge in a tree.  "branch" is a
   generally more common synonym.

   (1998-12-29)


The Free On-line Dictionary of Computing (30 December 2018):

Advanced RISC Computing Specification
ARC
ARCS

    (ARC, previously ARCS) The baseline
   hardware requirements for an ACE-compatible system.

   (1995-01-16)