demonstrator vs instructor

demonstrator and instructor both are nouns.

Word	Noun	Adjective	Verb	Adverb
demonstrator	Yes	No	No	No
instructor	Yes	No	No	No

As nouns, instructor is a hypernym of demonstrator; that is, instructor is a word with a broader meaning than demonstrator:

demonstrator: a teacher or teacher's assistant who demonstrates the principles that are being taught
instructor: a person whose occupation is teaching

Other hypernyms of demonstrator include teacher.

demonstrator (noun)	instructor (noun)
someone who participates in a public display of group feeling	a person whose occupation is teaching
someone who demonstrates an article to a prospective buyer
a teacher or teacher's assistant who demonstrates the principles that are being taught