1. A pile of earth, gravel, sand, rocks, or debris heaped for protection or concealment.
2. A natural elevation, such as a small hill.
3. A raised mass, as of hay; a heap. See synonyms at heap.
4. Archaeology. A large artificial pile of earth or stones often marking a burial site.
5. Baseball. The slightly elevated pitcher's area in the center of the diamond.
6. Archaic. A hedge or fence.

1. To fortify or conceal with a mound.
2. To heap into a raised mass.

[Origin unknown.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.