rah (rä)interj. Used as an exclamation of approval or encouragement.[Short for hurrah.]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.rah (r??) interjinformal chiefly US short for hurrahCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014rah (r?) interj. (used as an exclamation of encouragement to a player or team.) [1865?70; short for hurrah] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.