Definitions for "SPST"
Keywords:  pole, throw, spnc, spno, switch
Single Pole Single Throw. A relay that has only one pole or contact and can only throw or make electrical contact with one stationary contact.
A Single Pole Single Throw switch has a common terminal and either a normally open terminal (SPNO) or a normally closed terminal (SPNC).
Single Pole Single Throw. Normal circuit configuration in a membrane switch.