Gage pressure
Pressure measured with respect to atmospheric pressure.

Gas
A state of matter in which the material has very low density and viscosity; can expand and contract greatly in response to changes in temperature and pressure; easily diffuses into other gases; readily and uniformly distributes itself throughout any container. A gas can be changed to the liquid or solid state only by the combined effect of increased pressure and decreased temperature. Examples include sulfur dioxide, ozone, and carbon monoxide.

Gram (g)
A metric unit of weight. One ounce equals 28.4 grams.