Tian·an·men Square (tyän?än?m?n?) An extensive open area in central Beijing, China, the world’s largest public square. Adjacent to the Forbidden City, it has long been the site of festivals, rallies, and demonstrations. In 1989 Chinese troops fired on student demonstrators, killing an estimated 2,000 or more.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.Tian?an?men Square? (?ty?n ?n?m?n) also Tienanmen Square n. a large plaza in Beijing, China. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.