Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
a bolt with an attachment that expands as the bolt is screwed in so as to anchor it in place, used in holes drilled in stone, concrete, etc.
Used by arrangement with John Wiley & Sons, Inc.
nounThe 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 bolt having an attachment that expands as the bolt is driven into a surface.