deviation

dee-vee-AY-shun /ˌdiːviˈeɪʃən/
nounC1GREGMATIELTS
formaltechnicalscientific

The action of departing from an established course or accepted standard.

In quality control, a deviation is any instance where the actual result differs from the expected specification.

The story behind the word. The word literally means 'going away from the way'. It comes from the Latin 'deviare'. If the 'way' is the correct process or standard, a 'deviation' is when you step off that path and wander into the woods of error.

Word relationships

  • divergence: Divergence is a moving away in different directions; deviation is a departure from a single set path.
  • conformity: Conformity is compliance with standards, rules, or laws.

Commonly confused with

  • variation: Variation is a natural difference; deviation is a departure from a required standard.

Word family

  • deviate (verb): To depart from an established course.
  • deviant (adjective): Departing from usual or accepted standards.

Collocations

  • standard deviation
  • allowable deviation
  • minor deviation

Idioms & expressions

  • deviation from the norm

Example sentences

  • "Standard deviation is a measure of the amount of variation or dispersion of a set of values." Statistics
  • "Any deviation from the assigned flight path must be reported to air traffic control immediately." Aviation

Memory hook

Deviation is a 'De-Via-tion'—taking a 'D-tour' away from the 'Via' (road). Stepping off the path.

When not to use

Don't use 'deviation' when you mean a 'mistake' that is easily fixed; it refers to a measurable distance from a norm.

Fun facts

  • In social science, 'positive deviance' refers to people who find better solutions to problems despite having the same resources as their peers.
  • Magnetic deviation is the error in a compass reading caused by local magnetic fields.

Related words

defect, tolerance, rectify

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