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]

The Free On-line Dictionary of Computing (19 January 2023):

Advanced RISC Computing Specification
ARC
ARCS

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

   (1995-01-16)


The Free On-line Dictionary of Computing (19 January 2023):

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)