A flavorless, naturally effervescent water that takes its name from the town of Nieder Selters in the Weisbaden region of Germany. Human-made "seltzer," also referred to as soda water, was introduced in the latter half of the 18th century when carbon dioxide was injected into water. The original seltzer was the forerunner to soda pops, which came into being in the 1840s when flavors were added to seltzer water. See also soda water.