1. A piece of thin crisp toast.
2. An hors d'oeuvre made with a crostino and any of various toppings.

[Italian, diminutive of crosta, crust, from Latin crūsta.]

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.