Dae·gu (d?-go?o?) also Tae·gu (t?-) A city of southeast South Korea north-northwest of Busan. It is an industrial and commercial center.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.