World War In. Abbr. WWI A war fought from 1914 to 1918, in which Great Britain, France, Russia, Belgium, Italy, Japan, the United States, and other allies defeated Germany, Austria-Hungary, Turkey, and Bulgaria.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.World War I n (Historical Terms) the war (1914?18), fought mainly in Europe and the Middle East, in which the Allies (principally France, Russia, Britain, Italy after 1915, and the US after 1917) defeated the Central Powers (principally Germany, Austria-Hungary, and Turkey). The war was precipitated by the assassination of Austria’s crown prince (Archduke Franz Ferdinand) at Sarajevo on June 28, 1914 and swiftly developed its major front in E France, where millions died in static trench warfare. After the October Revolution (1917) the Bolsheviks ended Russian participation in the war (Dec 15, 1917). The exhausted Central Powers agreed to an armistice on Nov 11, 1918 and quickly succumbed to internal revolution, before being forced to sign the Treaty of Versailles (June 28, 1919) and other treaties. Also called: First World War or Great War Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014World War I n. the war fought mainly in Europe and the Middle East, between the Central Powers and the Allies, beginning on July 28, 1914, and ending on Nov. 11, 1918, with the collapse of the Central Powers. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.