/ ˌdiːviˈeɪʃn; NAmE / noun deviation (from sth)
1.
[ U , C ] the act of moving away from what is normal or acceptable; a difference from what is expected or acceptable :
deviation from the previously accepted norms
sexual deviation
a deviation from the plan
2.
[ C ] ( technical ) the amount by which a single measurement is different from the average :
a compass deviation of 5° (= from true north)
—see also standard deviation
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WORD ORIGIN
late Middle English : via French from medieval Latin deviatio(n-) , from Latin deviare , from de- away from + via way.