Literally "water without carbonation"; usually bottled. This is typical of Spain, central, and South American (like Peru) Spanish-speaking countries.
As the gringo says: Quiero ordenar agua sin gas por favor.
by Darren Y. July 13, 2006
Still water, as it would be ordered in southern Spain.
Agua sin gas, por favore.
by Kung-Fu Jesus April 30, 2004