definition of
gas

[1] #1 gas n. [gaseous state] the state of matter distinguished from the solid and liquid states by: relatively low density and viscosity; relatively great expansion and contraction with changes in pressure and temperature; the ability to diffuse readily; and the spontaneous tendency. wn

[2] #2 gas n. a fluid in the gaseous state having neither independent shape nor volume and being able to expand indefinitely. wn

[3] #3 gas n. [gasoline, gasolene, petrol] a volatile flammable mixture of hydrocarbons (hexane and heptane and octane etc.) derived from petroleum; used mainly as a fuel in internal-combustion engines. wn

[4] #4 gas v. attack with gas; subject to gas fumes; "The despot gassed the rebellious tribes". wn

[5] #5 gas n. [flatulence, flatulency] a state of excessive gas in the alimentary canal. wn