Hi·lo (h??l?) A city of Hawaii on the eastern coast of the island of Hawaii on Hilo Bay, an inlet of the Pacific Ocean. Settled in the 1820s by American missionaries, the city grew as a shipping port, especially for sugarcane, and as a tourist 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.Hi?lo (?hi lo?) n. a seaport on E Hawaii island, in SE Hawaii. 35,269. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.