aberration

ab*er*ra*tion

noun

{bc}the fact or an instance of deviating or being {d_link|aberrant|aberrant:1} especially from a moral {d_link|standard|standard:1} or normal state

chromatic aberration

noun

{bc}aberration caused by the differences in refraction of the colored rays of the spectrum

spherical aberration

noun

{bc}aberration that is caused by the spherical form of a lens or mirror and that gives different foci for central and marginal rays