For her, such a low grade on an exam was an aberration.
a study of sexual aberration
Recently geneticists have taken a closer look at a genetic aberration previously considered rare … . The genes may be perfectly normal, yet there is a shortage or surplus of DNA sequences that may play a role in diseases that defy straightforward genetic patterns … —Melinda Wenner, Scientific American, June 2009
He did hit five homers for Texas in 1987, but that was an aberration. In no other major league season has he hit more than three, and last season he actually came up with a goose egg. —E.M. Swift, Sports Illustrated, 5 Apr. 1989
Gilliard's studies of numerous bird of paradise species brought them from the realm of exotic aberrations to the forefront of sociobiology. —Jared M. Diamond, Nature, 24-30 Sept. 1981
Deviation of light rays by lenses or curved mirrors which causes the images to be blurred. Spherical aberration occurs because curvature in a lens or mirror causes rays falling on the outer edges to be brought to a focus at a different point than those falling on the middle. This makes the images formed appear blurred. Chromatic aberration, which occurs in lenses but not mirrors, is the failure of a lens to focus all colours (wavelengths) of light in the same plane; the image appears blurred and shows rainbow-coloured fringes around the edges. See alsoastigmatism.