The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
A depression in the floor of the northern Pacific Ocean off northeast Japan. It extends from the Bonin to the Kuril islands and reaches depths of more than 9,000 m (30,000 ft).