ignitron noun. 
[ɪg'nʌɪtrɒn] M20.[from IGNITE verb, IGNITION + -TRON.]Electronics. A mercury-arc rectifier of a kind having a pool cathode, a single anode, and an igniter, the timing of the igniter being used to control the rectifier output. Cf. 
EXCITRON. 
 [TahlilGaran] English Dictionary ▲