1. A wandering or straying away; a departure or deviation from what is considered normal or from the socially recognized path: The horror novel was considered an aberration as far as the tastes of the reading public were concerned.

The new rules of the club were confusing and full of aberrations.

2. A defect in a lens or mirror, causing a distorted image or one with colored edges: The blurred photographs indicate that Ron's camera has a lens with an aberration.

The flaw in a lens that doesn't focus properly is called a spherical aberration.

3. In astronomy, a small periodic change in the apparent position of a star or other astronomical object, caused by the motion of the earth around the sun: The astronomer noticed an unusual aberration in the constellations of the Northern Hemisphere.

In astronomy, an aberration is an apparent displacement in the position of a celestial object as a result of the time it takes for light from the object to reach an earthbound observer and to the orbital motion of the earth during that time.

4. A disorder or abnormal alteration in one's mental state: Three authors got together to see how many aberrations they could include in the Worst Novel of the Year.

The only aberration that Marcia's mother has is an occasional lapse of memory.

1. An aberration arising from the fact that rays which are initially at different distances from the optical axis come to a focus at different distances along the axis when they are reflected from a spherical mirror or refracted by a lens with spherical surfaces.
2. A fault in a lens or curved mirror in which light passing through the edge has a different focal point from light passing through the center, resulting in blurred images.
3. The blurring of an image that occurs when light from the margin of a lens or mirror with a spherical surface comes to a shorter focus than light from the central portion.

The changing focal length is caused by deviations in the lens or mirror surface from a true sphere.