Strictly speaking, seltzer water (or just "seltzer") is a particular type of carbonated mineral water. The Oxford English Dictionary defines it as "an effervescent mineral water obtained near Nieder-Selters, containing sodium chloride and small quantities of sodium, calcium, and magnesium carbonates," or any artificial imitation of that formula. The name comes from the German "Selterser," or "from Seltser," the village in Germany where springs producing this water were located.
mineral water containing free carbon dioxide, obtained originally from springs at Niederselters, Germany. Reputed to have curative value in treating several diseases, it became very popular in the 19th cent. In the 20th cent. it was produced synthetically and, as soda water, is widely used as a beverage, often lightly flavored, as well as a component of other beverages.
The Columbia Encyclopedia, Sixth Edition. Copyright © 2002 Columbia University Press