A·vo·ga·dro (ä?v?-gä?dr?, ä?v?-), Amedeo 1776-1856. Italian chemist and physicist who advanced the hypothesis that has come to be called Avogadro’s law (1811). From this hypothesis other physicists were able to calculate Avogadro’s number.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.Avogadro (?æv?????dr??; Italian avo??a?dro) n (Biography) Amedeo (ame?d??o), Conte di Quaregna. 1776?1856, Italian physicist, noted for his work on gasesCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014A?vo?ga?dro (?? v??g? dro?) n. Count Amadeo, 1776?1856, Italian physicist and chemist. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.