flashover vs arc

flashover and arc both are nouns.

Word	Noun	Adjective	Verb	Adverb
flashover	Yes	No	No	No
arc	Yes	No	Yes	No

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

flashover: an unintended electric discharge (as over or around an insulator)
arc: electrical conduction through a gas in an applied electric field

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

flashover (noun)	arc (noun)
an unintended electric discharge (as over or around an insulator)	electrical conduction through a gas in an applied electric field
	a continuous portion of a circle
	something curved in shape

flashover (verb)	arc (verb)
	form an arch or curve