Origin: Latin suffix -tion
Deviation has 6 different meanings across 1 category:
a variation that deviates from the standard or norm
"the deviation from the mean"
the difference between an observed value and the expected value of a variable or function
"The statistical analysis showed that every measurement had a small deviation from the predicted average."
the error of a compass due to local magnetic disturbances
"The captain adjusted their course to correct for the significant deviation caused by the ship's heavy iron hull."
a turning aside (of your course or attention or concern)
"a diversion from the main highway"
"a digression into irrelevant details"
"a deflection from his goal"
The act of deviating; wandering off the correct or true path or road
"The pilot's sudden deviation from the flight path caused a delay in their arrival."
In plain English: Deviation is when something goes off course from what was expected or planned.
"The GPS showed that we were taking a significant deviation from our planned route to avoid traffic."
Usage: Use deviation to describe any departure from an expected standard, rule, or planned route. It is often confused with variation, but while a variation implies a natural difference in degree, a deviation suggests straying away from what was intended or required.
The word entered English via Middle French and Medieval Latin as a noun formed by adding the suffix "-tion" to "deviate." Its original meaning of an act or process of turning aside has remained consistent with its current definition.