de·vi·a·tion / ˌdēvēˈāshən/ • n. 1. the action of departing from an established course or accepted standard: deviation from a norm sexual deviation | deviations from standard English. 2. Statistics the amount by which a single measurement differs from a fixed value such as the mean.3. the deflection of a vessel’s compass needle caused by iron in the vessel, which varies with the vessel’s heading.DERIVATIVES: de·vi·a·tion·ism / -ˌizəm/ n.de·vi·a·tion·ist / -ist/ n.

deviation (dee-vi-ay-shŏn) n.
1. (in ophthalmology) any abnormal position of one or both eyes. Deviations of both eyes may occur in brain disease. Deviations of one eye come into the category of squint (see strabismus). dissociated vertical d. an acquired condition, chiefly associated with infantile esotropia (convergent strabismus), in which one eye looks upwards when it is covered.

2. see sexual deviation.