demo vs display

demo and display both are nouns.

Word	Noun	Adjective	Verb	Adverb
demo	Yes	No	Yes	No
display	Yes	No	Yes	No

As nouns, display is a hyponym of demo; that is, display is a word with a more specific, narrower meaning than demo:

demo (noun)	display (noun)
a visual presentation showing how something works	something shown to the public
	a visual representation of something
	an electronic device that represents information in visual form
	exhibiting openly in public view
	something intended to communicate a particular impression
	behavior that makes your feelings public

demo (verb)	display (verb)
give an exhibition of to an interested audience	to show, make visible or apparent
	attract attention by displaying some body part or posing; of animals