electric glow vs electric arc

electric glow and electric arc both are nouns.

Word	Noun	Adjective	Verb	Adverb
electric glow	Yes	No	No	No
electric arc	Yes	No	No	No

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

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

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

electric glow (noun)	electric arc (noun)
an electrical discharge accompanied by ionization of surrounding atmosphere	electrical conduction through a gas in an applied electric field