tympanic membranen. See eardrum.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.tympanic membrane n (Anatomy) anatomy the thin translucent oval membrane separating the external ear from the middle ear. It transmits vibrations produced by sound waves, via the ossicles, to the cochlea. Also called: tympanum Nontechnical name: eardrum Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014ear?drum (???r?dr?m) n. a membrane in the ear canal between the external ear and the middle ear; tympanic membrane. [1635?45] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.tym·pan·ic membrane (t?m-p?n??k) See eardrum.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.tympanic membrane(or eardrum) A membrane between the external and middle ear.Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited