deviation

noun

de·​vi·​a·​tion ˌdē-vē-ˈā-shən 

: an act or instance of deviating: such as

a

navigation : deflection of the needle of a compass caused by local magnetic influences (as in a ship)

b

mathematics : the difference between a value in a frequency distribution and a fixed number (such as the mean)

c

: departure from an established ideology or party line

deviation from Communist orthodoxy

d

: noticeable or marked departure from accepted norms (see norm sense 2) of behavior

deviationism

ˌdē-vē-ˈā-shə-ˌni-zəm 

noun

deviationist

ˌdē-vē-ˈā-sh(ə-)nist 

noun or adjective

Synonyms of deviation

• departure
• detour
• divergence
• deflection

Examples of deviation in a Sentence

There have been slight deviations in the satellite's orbit.

Having juice instead of coffee was a deviation from his usual routine.

The pattern's deviation from the norm is significant.

Recent Examples on the Web

But there are tiny systemic deviations at small angles in that orientation, which in turn create the twisted structure. — Jennifer Ouellette, ArsTechnica, 18 Aug. 2026

The three spacecraft will beam lasers at each other, looking for deviations in the travel time of those laser beams as evidence for the passing of a long-wavelength gravitational wave. — Keith Cooper, Space.com, 17 Aug. 2026

Her sari—royal-purple silk stitched with miniature golden birds—hung straight down without any visible deviation in service to hips or buttocks. — Madhuri Vijay, New Yorker, 16 Aug. 2026

To be clear, the success of a good adaptation isn’t necessarily its faithfulness to the source material, but major deviations from the book are far from the only problems here. — Louis Peitzman, Vulture, 13 Aug. 2026

Word History

Etymology

see deviate entry 1

First Known Use

15th century, in the meaning defined above

Phrases Containing deviation

• mean deviation
• mean square deviation
• standard deviation

Rhymes for deviation

• ablation
• aeration
• bination
• carnation
• cassation
• castration
• causation
• centration
• cessation
• cetacean
• chelation
• citation

Kids Definition

deviation

noun

de·​vi·​a·​tion ˌdē-vē-ˈā-shən 

: an act or instance of deviating: as

a

: the difference found by subtracting some fixed number (as the arithmetic mean of a series of statistical data) from any item of the series

b

: noticeable difference from accepted standards (as of behavior or morals)

Medical Definition

deviation

noun

de·​vi·​a·​tion ˌdē-vē-ˈā-shən 

: an act or instance of diverging from an established way or in a new direction: as

a

: evolutionary differentiation involving interpolation of new stages in the ancestral pattern of morphogenesis

b

: noticeable or marked departure from accepted norms of behavior