ab·er·ra·tion noun

the fact or an instance of deviating or being aberrant especially from a moral standard or normal state

: failure of a mirror, refracting surface, or lens to produce exact point-to-point correspondence between an object and its image

: unsoundness or disorder of the mind

: a small periodic change of apparent position in celestial bodies due to the combined effect of the motion of light and the motion of the observer