Also referred to as soda-lime glass. This type, being cheap, accounts for most of the glass manufactured today. Soda glass draws its name from the soda (Na2O) and lime (CaO) elements added to the Silica (sand or SiO2 to sound official). Makeup varies depending on the manufacturer but you can count on most soda glass being between 60-75% silica, 12-18% soda, and 5-12% lime.
When one discusses glassware, lead glass is favored by collectors. Lead glass is what makes up crystal and it also has a nice ring to it when tapped. Soda glass, on the other hand, sounds rather hollow when tapped.