One of the most important devices of the last century spent its first months without a name. Its inventors had a working model in December 1947 and no word for it until May 1948.
At Bell Labs in Murray Hill, New Jersey, John Bardeen and Walter Brattain successfully tested the device on December 16, 1947. The Linda Hall Library describes a small plastic wedge wrapped in gold foil, sliced at the tip and pressed onto a piece of germanium. It could amplify a signal, a job that until then needed a vacuum tube.
Naming it became a committee matter. According to the Linda Hall Library, a group organized by Ralph Bown, Bell Labs' vice president for research, circulated a memo in May 1948 listing about six options. They included "Semiconductor Triode" and "Iotatron." When the ballots were counted, transistor won.
The word came from John R. Pierce, a Bell Labs engineer. The PBS series Transistorized!, drawing on an interview with Pierce, says Brattain bumped into him in a hallway and asked for ideas. His reasoning was technical. Just as the vacuum tube had a property called transconductance, the new amplifier had one called "transresistance."
Pierce also wanted the word to fit with recent device names like varistor and thermistor. Both were blends ending in the tail of resistor. Dictionary.com dates varistor, from "variable resistor," to 1940-45. Merriam-Webster dates thermistor, from "thermal resistor," to 1940.
Not every source tells the blend the same way. Etymonline gives transfer plus resistor, "so called because it transfers an electrical current across a resistor." The Linda Hall Library says the naming memo itself gave "transconductance" or "transfer" plus "varistor." Pierce's own account is the closest to the event, and Etymonline itself says the word is only "said to have been coined" by him.
The tail end has a long history. Etymonline traces resistor to the late 14th century, when a resistour was a person who resisted. It has named the electrical device since about 1900.
Bell Labs announced the transistor at a press conference in New York on June 30, 1948. The New York Times gave it only a few paragraphs. By 1958, Etymonline notes, English had the transistor radio.