interval vs separation

interval and separation both are nouns.

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

As nouns, interval and separation are synonyms defined as:

interval (noun)	separation (noun)
the distance between things	the social act of separating or parting company
a set containing all points (or all real numbers) between two given endpoints	the act of dividing or disconnecting
the difference in pitch between two notes	(law) the cessation of cohabitation of man and wife (either by mutual agreement or under a court order)
a definite length of time marked off by two instants	sorting one thing from others
	the distance between things
	coming apart
	the termination of employment (by resignation or dismissal)
	the space where a division or parting occurs
	the state of lacking unity