spherical aberrationParallel light rays passing through a lens with a spherical surface focus at different points depending on whether they pass through the lens closer to the edge or closer to the center.spherical aberrationn. 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.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.spherical aberration n (General Physics) physics a defect of optical systems that arises when light striking a mirror or lens near its edge is focused at different points on the axis to the light striking near the centre. The effect occurs when the mirror or lens has spherical surfaces. See also aberration4 Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014