A departing from what is prescribed
The condition of being abnormal
Serious mental illness or disorder impairing a person's capacity to function normally and safely
She is normally calm and level headed, so this outburst is an aberration.
The discovery of the aberration of light in 1725, due to James Bradley, is one of the most important in the whole domain of astronomy.
We considered our defeat to be an aberration, since we'd easily beaten this team last season.
It has been in the past a source of much perplexity to observers of transits, but is now understood to be a result of irradiation, produced by the atmosphere or by the aberration of the telescope.
The chromatic aberration of the object-glass of one of these telescopes is corrected for photographic rays, and the image formed by it is received on a highly sensitive photographic plate.