injector vs gismo

injector and gismo both are nouns.

Word	Noun	Adjective	Verb	Adverb
injector	Yes	No	No	No
gismo	Yes	No	No	No

As nouns, gismo is a hypernym of injector; that is, gismo is a word with a broader meaning than injector:

injector: a contrivance for injecting (e.g., water into the boiler of a steam engine or particles into an accelerator etc.)
gismo: a device or control that is very useful for a particular job

Other hypernyms of injector include appliance, contraption, contrivance, convenience, gadget, gizmo, widget.

injector (noun)	gismo (noun)
a contrivance for injecting (e.g., water into the boiler of a steam engine or particles into an accelerator etc.)	a device or control that is very useful for a particular job
An injector, ejector, steam ejector, steam injector, eductor-jet pump or thermocompressor is a type of pump.	something unspecified whose name is either forgotten or not known