An icing made of powdered sugar, egg whites and a few drops of lemon juice. It hardens when dry, making it a favorite for durable decorations (such as flowers and leaves) and ornamental writing. Royal icing is often tinted with food coloring.
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.