Du·bai also Du·bayy (do?o-b??) A city and sheikhdom of eastern United Arab Emirates on the Persian Gulf. Oil was discovered here in the 1960s, and in subsequent decades Dubai has grown into an international business hub.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.Dubai (du??ba?) n (Placename) a sheikhdom in the NE United Arab Emirates, consisting principally of the port of Dubai, on the Persian Gulf: oilfields. Pop: 1 026 000 (2005 est)Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014Du?bai (du?ba?) n. 1. an emirate in the NE United Arab Emirates, on the Persian Gulf. 419,104. 2. the capital of the emirate of Dubai. 585,189. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.