TVS diodes for ESB protection, bidirectional TVS diode, TVS diodes array

PTVS Series 400 W 9.2 V Uni-Directional Surface Mount TVS Diode - SOD-123W, What is TVS diode, Uni Directional TVS diode, silicon voltage suppressor, Transient Voltage Suppressor Diode, Uni-Directional Zener TVS Diode