an·ti·gen (?n?t?-j?n) also an·ti·gene (-j?n?)n. A molecule that is capable of binding to an antibody or to an antigen receptor on a T cell, especially one that induces an immune response. An antigen is usually a foreign substance, such as a toxin or a component of a virus, bacterium, or parasite.an?ti·gen?ic (-j?n??k) adj.an?ti·gen?i·cal·ly adv.an?ti·ge·nic?i·ty (-j?-n?s??-t?) n.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.antigen (?ænt?d??n; -?d??n) or antigenen (Biochemistry) a substance that stimulates the production of antibodies[C20: from anti(body) + -gen] ?anti?genic adj ?anti?genically advCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014an?ti?gen (?æn t? d??n, -?d??n) n. 1. any substance that can stimulate the production of antibodies and combine specifically with them. 2. any commercial substance that, when injected or absorbed into animal tissues, stimulates the production of antibodies. 3. antigens of a particular type collectively. [1905?10; anti (body) + -gen] an`ti?gen?ic, adj. an`ti?gen?i?cal?ly, adv. an`ti?ge?nic?i?ty (-d???n?s ? ti) n. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.an·ti·gen (?n?t?-j?n) A substance that stimulates the production of an antibody when introduced into the body. Antigens include toxins, bacteria, viruses, and other foreign substances. See Note at blood type.The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.antigenA molecule recognized as foreign by the body?s immune system, causing the release of antibodies.Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited