An early form of triode valve, developed by Lee De Forest and used as a detector and amplifier for radio signals. Frequently attributive, as "audion amplifier", "audion tube", etc.
Origin
Early 20th century. From classical Latin audīre to hear + -on.
Definition of audion in US English:
audion
nounˈɔːdɪɒn
Radio historical
An early form of triode valve, developed by Lee De Forest and used as a detector and amplifier for radio signals. Frequently attributive, as "audion amplifier", "audion tube", etc.
Origin
Early 20th century. From classical Latin audīre to hear + -on.