The Collaborative International Dictionary of English v.0.48:

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.
   [Webster 1913 Suppl.] Choky

WordNet (r) 3.0 (2006):

choking coil
    n 1: a coil of low resistance and high inductance used in
         electrical circuits to pass direct current and attenuate
         alternating current [syn: choke, choke coil, choking
         coil]