Source : Webster's Revised Unabridged Dictionary (1913)

Choking coil \Choking coil\ (Elec.)
   A coil of small resistance and large inductance, used in an
   alternating-current circuit to impede or throttle the
   current, or to change its phase; -- called also {reactance
   coil} or {reactor}, these terms being now preferred in
   engineering usage.

Source : WordNet®

choking coil
     n : a coil of low resistance and high inductance used in
         electrical circuits to pass direct current and attenuate
         alternating current [syn: {choke}, {choke coil}]