How Well Do You Know English Slang?
c.1300, "running, flowing," from Old French corant "running, lively, eager, swift," present participle of corre "to run," from Latin currere "to run, move quickly" (of persons or things), from PIE *kers- "to run" (cf. Greek -khouros "running," Lithuanian karsiu "go quickly," Old Norse horskr "swift," Old Irish and Middle Welsh carr "cart, wagon," Breton karr "chariot," Welsh carrog "torrent"). Meaning "prevalent, generally accepted" is from 1560s.
late 14c., from Middle French corant (Modern French courant), from Old French corant (see current (adj.)). Applied 1747 to the flow of electrical force.
current cur·rent (kûr'ənt, kŭr'-)
A stream or flow of a liquid or gas.
Symbol I A flow of electric charge.
Symbol I, i The amount of electric charge flowing past a specified circuit point per unit time.
Our Living Language : Electric current is the phenomenon most often experienced in the form of electricity. Any time an object with a net electric charge is in motion, such as an electron in a wire or a positively charged ion jetting into the atmosphere from a solar flare, there is an electric current; the total current moving through some cross-sectional area in a given direction is simply the amount of positive charge moving through that cross-section. Current is sometimes confused with electric potential or voltage, but a voltage difference between two points (such as the two terminals of a battery) means only that current can potentially flow between them; how much does in fact flow depends on the resistance of the material between the two points. Electrical signals transmitted through a wire generally propagate at nearly the speed of light, but the current in the wire actually moves very slowly: pushing electrons into one end of the wire is rather like pushing a marble into one end of a tube filled with marbles—a marble (or electron) gets pushed out the other end almost instantly, even though the marbles (or electrons) inside move only incrementally.
The quantity of charge per unit time, measured in Amperes (Amps, A). By historical convention, the sign of current is positive for currents flowing from positive to negative potential, but experience indicates that electrons are negatively charged and flow in the opposite direction.