electric company vs utility

electric company and utility both are nouns.

Word	Noun	Adjective	Verb	Adverb
electric company	Yes	No	No	No
utility	Yes	Yes	No	No

As nouns, utility is a hypernym of electric company; that is, utility is a word with a broader meaning than electric company:

electric company: a public utility that provides electricity
utility: a company that performs a public service; subject to government regulation

Other hypernyms of electric company include public-service corporation, public utility, public utility company.

electric company (noun)	utility (noun)
a public utility that provides electricity	the service (electric power or water or transportation) provided by a public utility
	a facility composed of one or more pieces of equipment connected to or part of a structure and designed to provide a service such as heat or electricity or water or sewage disposal
	the quality of being of practical use
	(computer science) a program designed for general support of the processes of a computer
	a company that performs a public service; subject to government regulation
	(economics) a measure that is to be maximized in any situation involving choice

electric company (adjective)	utility (adjective)
	used of beef; usable but inferior
	capable of substituting in any of several positions on a team