nouns
an apparatus that produces a vapor or gas
is a type of (narrower)
equipment designed to serve a specific function
engine that converts mechanical energy into electrical energy by electromagnetic induction
is a type of (narrower)
motor that converts thermal energy to mechanical work
someone who originates or causes or initiates something
"he was the generator of several complaints"
an electronic device for producing a signal voltage
is a type of (narrower)
a device that accomplishes its purpose electronically