The Collaborative International Dictionary of English v.0.48:

Direct current \Direct current\ (Elec.)
   (a) A current flowing in one direction only; -- distinguished
       from alternating current. When steady and not pulsating
       a direct current is often called a continuous current.
   (b)

   A direct induced current, or momentary current of the same
      direction as the inducing current, produced by stopping or
      removing the latter; also, a similar current produced by
      removal of a magnet.
      [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

electric current \electric current\, electrical current
\electrical current\,
   the movement of electrically charged particles, atoms, or
   ions, through solids, liquids, gases, or free space; the term
   is usually used of relatively smooth movements of electric
   charge through conductors, whether constant or variable.
   Sudden movements of charge are usually referred to by other
   terms, such as spark or lightning or discharge. In
   metallic conductors the electric current is usually due to
   movement of electrons through the metal. The current is
   measured as the rate of movement of charge per unit time, and
   is counted in units of amperes. As a formal definition, the
   direction of movement of electric current is considered as
   the same as the direction of movement of positive charge, or
   in a direction opposite to the movement of negative charge.
   Electric current may move constantly in a single direction,
   called direct current (abbreviated DC), or may move
   alternately in one direction and then the opposite direction,
   called alternating current (abbreviated AC).
   [PJC]

WordNet (r) 3.0 (2006):

direct current
    n 1: an electric current that flows in one direction steadily
         [syn: direct current, DC, direct electric current]
         [ant: AC, alternating current, alternating electric
         current]

Moby Thesaurus II by Grady Ward, 1.0:

37 Moby Thesaurus words for "direct current":
   AC, DC, absorption current, active current, alternating current,
   conduction current, convection current, cycle, delta current,
   dielectric displacement current, displacement current,
   eddy current, electric current, electric stream, emission current,
   exciting current, free alternating current, galvanic current,
   high-frequency current, idle current, induced current,
   induction current, ionization current, juice,
   low-frequency current, magnetizing current, multiphase current,
   pulsating direct current, reactive current, rotary current,
   single-phase alternating current, stray current,
   thermionic current, thermoelectric current,
   three-phase alternating current, voltaic current, watt current