Rectifying tube and Thermionic valve

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

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

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

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