Plasma is one of the four fundamental states of matter (the others being solid, liquid, and gas). Heating a gas may ionize its molecules or atoms (reducing or increasing the number of electrons in them), thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions.

A perennial stream or perennial river is a stream or river (channel) that has continuous flow in parts of its stream bed all year round during years of normal rainfall. "Perennial" streams are contrasted with "intermittent" streams which normally cease flowing for weeks or months each year, and with "ephemeral" channels that flow only for hours or days following rainfall.

The title Grandmaster is awarded to chess players by the world chess organization FIDE. Apart from World Champion, Grandmaster is the highest title a chess player can attain. Once achieved, the title is held for life.

USS Gilliam (APA-57), named for Gilliam County in Oregon, was the lead ship in the her class of attack transports serving in the United States Navy during World War II. She was launched 28 March 1944 under a Maritime Commission contract by the Consolidated Steel Corporation, Wilmington, California; sponsored by Mrs. A. O. Williams of Wilmington; acquired 31 July 1944; and commissioned 1 August 1944, Comdr. H. B. Olsen in command.

The Doppler effect (or Doppler shift), named after the Austrian physicist Christian Doppler, who proposed it in 1842 in Prague, is the change in frequency of a wave (or other periodic event) for an observer moving relative to its source. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. The received frequency is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession.