The story
Blend of thyratron (1930) + transistor (1947). First attested c. 1965, as an alternative name for the Silicon Controlled Rectifier (SCR) developed in the late 1950s.
Etymology from Wiktionary, CC BY-SA 4.0.
thyristor
Today it means: A semiconductor diode having an extra "gate" terminal to switch it on. Full definition →