deviation

(noun) a variation that deviates from the standard or norm. Synonyms: divergence, departure, difference. Example: "The deviation from the mean."

(noun) the difference between an observed value and the expected value of a variable or function.

(noun) the error of a compass due to local magnetic disturbances.

(noun) deviate behavior. Synonyms: deviance.

(noun) a turning aside (of your course or attention or concern). Synonyms: diversion, digression, deflection, deflexion, divagation. Examples: "A diversion from the main highway." "A digression into irrelevant details." "A deflection from his goal."