1. An electrically neutral ionized gas in an electric discharge; distinctly different from solids and liquids and normal gases.
2. A green slightly translucent variety of chalcedony used as a gemstone.
3. Fluid part of blood, etc; an ionized gas.
In physics, an ionized gas produced at extremely high temperatures, as in the Sun and other stars, which contains positive and negative charges in approximately equal numbers. It is a good electrical conductor. In thermonuclear reactions the plasma produced is confined through the use of magnetic fields.
(Physical chemistry) The gaseous state of hot ionized material consisting of ions and electrons and present in the stars and fusion reactors: sometimes regarded as a fourth state of matter distinct from normal gasses.