- thermometer (n.)
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- 1630s, from French thermomètre (1620s), coined by Jesuit Father Jean Leuréchon from Greek thermos "hot" (see thermal) + metron "measure" (see meter (n.2)). An earlier, Latinate form was thermoscopium (1610s). The earliest such device was Galileo's air-thermometer, invented c. 1597. The typical modern version, with mercury in glass, was invented by Fahrenheit in 1714. Related: Thermometric; thermometrical.