corona discharge vs arc

corona discharge and arc both are nouns.

Word	Noun	Adjective	Verb	Adverb
corona discharge	Yes	No	No	No
arc	Yes	No	Yes	No

As nouns, arc is a hypernym of corona discharge; that is, arc is a word with a broader meaning than corona discharge:

corona discharge: an electrical discharge accompanied by ionization of surrounding atmosphere
arc: electrical conduction through a gas in an applied electric field

Other hypernyms of corona discharge include discharge, electric arc, electric discharge, spark.

corona discharge (noun)	arc (noun)
an electrical discharge accompanied by ionization of surrounding atmosphere	electrical conduction through a gas in an applied electric field
	a continuous portion of a circle
	something curved in shape

corona discharge (verb)	arc (verb)
	form an arch or curve