Rectifying tube and Thermionic tube

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

Thermionic tube and rectifying tube are semantically related. In some cases you can use "Thermionic tube" instead a noun phrase "Rectifying tube".

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

Rectifying tube and thermionic tube are semantically related. Sometimes you can replace phrase "Rectifying tube" with "Thermionic tube", this phrases are similar.