Diode and Thermionic vacuum tube

Diode noun - A thermionic tube having two electrodes; used as a rectifier.

Thermionic vacuum tube and diode are semantically related. In some cases you can use "Thermionic vacuum tube" instead a noun "Diode".

Thermionic vacuum tube noun - Electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope.

Diode and thermionic vacuum tube are semantically related. Sometimes you can replace term "Diode" with "Thermionic vacuum tube", this terms are similar.