Also, hit the dirt. Fall to the ground, usually for protection. For example, As the planes approached, we hit the deck, or We heard shooting and hit the dirt. In the early 1900s the first expression was nautical slang for “jump out of bed,” or “wake up,” and somewhat later, “get going.” The current meaning dates from the 1920s.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.