Water that has been highly charged with carbon dioxide, which gives it effervescence. Soda water, also called club soda or just plain carbonated water, contains a small amount of sodium bicarbonate, which, because it's alkaline, can help neutralize an acidic stomach. Soda water is combined with sweeteners and flavorings to produce a variety of soft drinks. Many cocktails also use soda water as an ingredient. See also seltzer water.
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.