Definition of "hemagglutinin" [hemagglutinin]

• A substance, such as an antibody, that causes agglutination of red blood cells. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Flu vaccines and drugs focus on proteins found on the surface of the flu virus called hemagglutinin and neuraminidase, which give influenza A viruses their names, as in H5N1 or"
• "Flu vaccines and drugs focus on proteins found on the surface of the flu virus called hemagglutinin and neuraminidase, which give influenza A viruses their names, as in H5N1 or H1N1."
• "H1N1, the letters actually refer to the types of proteins found on the surface of a virus, namely hemagglutinin, as you can see there."