Styristors
Styristors are not a standard term for a defined electrical component in widely used reference works. The word often appears as a misspelling or mispronunciation of thyristor, a four-layer PNPN semiconductor switch used to control high-power signals. Because no canonical device bears the name styristor, definitions and usage vary, and some sources treat it as equivalent to a thyristor.
If styristor is intended to refer to a thyristor, the device is a latching current-controlled switch. It
Common applications include AC power control, motor speed regulation, and dimming in lighting systems, as well
In summary, styristor is not a distinct recognized component; the term most closely corresponds to thyristor