'Tesla coil' definitions:

Definition of 'Tesla coil'

From: WordNet
noun
A step-up transformer with an air core; used to produce high voltages at high frequencies

Definition of 'Tesla coil'

From: GCIDE
  • Tesla coil \Tes"la coil\, Tesla transformer \Tes"la trans*form"er\ [After N. Tesla, American electrician.] (Elec.) A transformer without iron, for high frequency alternating or oscillating currents; an oscillation transformer. [Webster 1913 Suppl.]