Water to which a small amount of vinegar, lemon or lime juice has been added. It's used as a soak to prevent discoloration of some fruits and vegetables (such as apples and artichokes) that darken quickly when their cut surfaces are exposed to air. It can also be used as a cooking medium.
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.