1. A dog of any of various breeds having a muscular body, broad powerful head, and short coat, especially an American pit bull terrier, an American Staffordshire terrier, or a Staffordshire bull terrier. Also called pit bull terrier.
2. Slang One who behaves in a markedly aggressive or ruthless manner.
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.