dead air vs intermission

dead air and intermission both are nouns.

Word	Noun	Adjective	Verb	Adverb
dead air	Yes	No	No	No
intermission	Yes	No	No	No

As nouns, intermission is a hypernym of dead air; that is, intermission is a word with a broader meaning than dead air:

dead air: an inadvertent interruption in a broadcast during which there is no sound
intermission: a time interval during which there is a temporary cessation of something

Other hypernyms of dead air include break, interruption, pause, suspension.

dead air (noun)	intermission (noun)
an inadvertent interruption in a broadcast during which there is no sound	the act of suspending activity temporarily
	a time interval during which there is a temporary cessation of something