ag·glu·ti·nin (?-glo?ot?n-?n)n. An antibody or other substance that is capable of causing agglutination, as of red blood cells or bacteria.[agglutin(ation) + -in.]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.agglutinin (???lu?t?n?n) n (Biology) a substance, such as an antibody or a lectin, that causes agglutination of cells or bacteria[C19: agglutinate + -in]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014ag?glu?ti?nin (??glut n ?n) n. an antibody that causes agglutination. [1895?1900] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.