digression vs deviation

digression and deviation both are nouns.

Word	Noun	Adjective	Verb	Adverb
digression	Yes	No	No	No
deviation	Yes	No	No	No

As nouns, digression and deviation are synonyms defined as:

digression and deviation: a turning aside (of your course or attention or concern)

Other synonyms of digression include deflection, deflexion, divagation, diversion.

digression (noun)	deviation (noun)
a turning aside (of your course or attention or concern)	deviate behavior
wandering from the main path of a journey	a turning aside (of your course or attention or concern)
a message that departs from the main subject	the error of a compass due to local magnetic disturbances
	the difference between an observed value and the expected value of a variable or function
	a variation that deviates from the standard or norm