f-stopf-stop (?f?st?p?)n.1. Abbr. f/ A camera lens aperture setting that corresponds to an f-number.2. See f-number.[f(ocal length) + stop.]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.f-stop n (Photography) any of the settings for the f-number of a camera Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014f-stop or f stop (??f?st?p) n. the setting of a camera lens aperture, as indicated by an f number. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.