1. Toute substance aériforme qui n'a pas de forme solide et qui tend ŕ se dilater.
2. Substance aériforme combustible utilisée surtout pour le chauffage ou pour cuisiner.
1. A fluid in the gaseous state having neither independent shape nor volume and being able to expand indefinitely.
2. 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.
3. Refined petroleum product used in combustion engines, fueling cars, trucks, etc.
A state of matter, in which the mollecules move freely and consequently the entire mass tends to expand indefinitely, occupying the total volume of any vessel into which it is introduced. Gases follow, within considerable degree of fidelity, certain laws relating their conditions of pressure, volume and temperature. Gases mix freely with each other, and they can be liquefied through compression or temperature reduction.
In physics, a form of matter, such as air, in which the molecules move randomly in otherwise empty space, filling any size or shape of container into which the gas is put.
A sugar-lump sized cube of air at room temperature contains 30 trillion molecules moving at an average speed of 500 meters per second (1,800 kph/1,200 mph). Gases can be liquefied by cooling, which lowers the speed of the molecules and enables attractive forces between them to bind them together.