am·y·loid (?m??-loid?)n.1. A starchlike substance.2. a. An insoluble, fibrous structure consisting chiefly of an aggregation of proteins arranged in beta sheets, forming extracellular deposits in organs or tissues and characteristic of certain diseases such as Alzheimer’s disease and Parkinson’s disease.b. The substance that makes up such a structure.adj.1. Starchlike.2. Being or related to proteinaceous amyloid: amyloid plaque.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.amyloid (?æm??l??d) n1. (Biochemistry) pathol a complex protein resembling starch, deposited in tissues in some degenerative diseases2. any substance resembling starchadjstarchlikeCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014am?y?loid (?æm ??l??d) n. 1. a waxy, translucent substance, composed primarily of protein fibers, that is deposited in various organs of animals in certain diseases. 2. a nonnitrogenous food consisting esp. of starch. adj. 3. of, resembling, or containing amylum. [1855?60] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.