separation vs interval

separation and interval both are nouns.

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

As nouns, separation and interval are synonyms defined as:

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