Pro·to-Ger·man·ic (pr??t?-jûr-m?n??k)n. The reconstructed prehistoric ancestor of the Germanic languages.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.Proto-Germanic n (Languages) the prehistoric unrecorded language that was the ancestor of all Germanic languages Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014Pro?to-Ger?man?ic (?pro? to? d??r?mæn ?k) n. the unattested prehistoric parent language of the Germanic languages. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.