Gas 03 : A fluid substance that completely fills any container in which it is confined and whose volume is dependent on the size of and pressure exerted upon the container. A gas is readily compressible. (WLOP)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}