Yal·ow (y?l??), Rosalyn Sussman 1921-2011. American medical physicist. She shared a 1977 Nobel Prize for developing the radioimmunoassay method and using it to measure peptide hormones such as insulin.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.Yal?ow (?yæl o?) n. Rosalyn Sussman, born 1921, U.S. medical physicist: Nobel prize for physiology or medicine 1977. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.