Rectifying valve and Thermionic valve

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

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

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

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