"device which stores electricity," 1926, from capacity, in reference to electrical conductors, with Latinate agent-noun ending.
1882, in the electrical sense, from arc (n.). Meaning "to move in an arc" is attested by 1940. Related: Arced; arcing.
unit of electrical energy, 1882, coined in recognition of British physicist James P. Joule (1818-1889). The surname is a variant of Joel. Related: Joulemeter.
by 1937 in reference to electrical transmission of sound and other signals, contracted from modulator-demodulator; see modulator.
small electronic device, 1948, from transfer + resistor, so called because it transfers an electrical current across a resistor. Said to have been coined by U.S. electrical engineer John Robinson Pierce (1910-2002) of Bell Telephone Laboratories, Murray Hill, N.J., where the device was invented in 1947. It took over many functions of the vacuum tube. Transistor radio is first recorded 1958.
Old English dælere "divider, distributor; agent, negotiator," agent noun from deal (v.). Meaning "player who passes out the cards in a game" is from c. 1600; meaning "one whose business is to buy and sell merchandise" is from 1610s. Meaning "purveyor of illegal drugs" is recorded by 1920.
unit of electrical power, 1882, in honor of James Watt (1736-1819), Scottish engineer and inventor. The surname is from an old pet form of Walter and also is in Watson.