A flat, small (usually 5- by 5- by 4-inch), triangle-shape tool, generally made of stainless steel. Each of the three edges has serrated teeth of a different size. This tool is used to make decorative designs and swirls in the frosting on a cake.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.