B lymphocyte also B-lym·pho·cyte (b??l?m?f?-s?t?)n. See B cell.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.B-lymphocyte n (Biochemistry) a type of lymphocyte, originating in bone marrow, that produces antibodies. Also called: B-cell See also T-lymphocyte Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014