meanwhile vs interval

meanwhile and interval both are nouns.

Word	Noun	Adjective	Verb	Adverb
meanwhile	Yes	No	No	Yes
interval	Yes	No	No	No

As nouns, interval is a hypernym of meanwhile; that is, interval is a word with a broader meaning than meanwhile:

Other hypernyms of meanwhile include time interval.

meanwhile (noun)	interval (noun)
the time between one event, process, or period and another	the distance between things
	a set containing all points (or all real numbers) between two given endpoints
	the difference in pitch between two notes
	a definite length of time marked off by two instants

meanwhile (adverb)	interval (adverb)
during the intervening time
at the same time but in another place