noun

deviation

dee-vee-AY-shun/ˌdiːviˈeɪʃn/

A departure from a reference course or value.

The map shows a slight deviation from our planned route.

A single route line detours away from a straight planned dotted path around a small obstruction; one short arrow shows departure, no words.

Etymology

deLatinoff, away

+viLatinway, road

+ationEnglishaction or result

With ‘off’ and ‘way’ at its core, deviation originally pictured going astray from the right path. A rule, standard, or plan can likewise serve as the path from which something departs.

In context

Libertarianism.org85:08

… it's not at all clear what happens if you have any deviation what the welfare implications are of even slight deviations from perfect contestability

Revising Traditional Notions of Competition and Monopoly - The Turney Collection

More examples

Any deviation from the safety procedure requires approval.
The sensor records small deviations from the expected temperature.
We measure each score's deviation from the class average.

Forms

deviation · deviations

deviate verb — To depart from a course or standard.

Similar words

departure: Emphasizes a break from an established practice or plan.
difference: Can compare any two values, without an expected standard.
divergence: Often emphasizes paths or values moving farther apart.