phanotron
/ˈfanətrɒn/(also phanatron) Electronics
noun
A thermionic diode rectifier utilizing an arc discharge in mercury vapour or gas at very low pressure.
Origin
1930s. Origin uncertain; perhaps from ancient Greek ϕαν-, stem of ϕαίνειν to bring to light, cause to appear + -o- + -tron. Originally a trade name.