step·fam·i·ly (st?p?f?m??-l?, -f?m?l?)n. pl. step·fam·i·lies A family with one or more stepchildren.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.stepfamily (?st?p?fæm?l?; ?st?p?fæml?) n, pl -liesa family created by a second union in which there are stepchildren or step-parentsCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014step?fam?i?ly (?st?p?fæm ? li, -?fæm li) n., pl. -lies. a family composed of a parent, a stepparent, and a child or children by a previous marriage. [1965?70] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.