thermometer
From Glossary of Meteorology
An instrument for measuring temperature by utilizing the variation of the physical properties of substances according to their thermal states.
Thermometers may be classified into six types according to their construction: gas thermometer, liquid-in-glass thermometer, deformation thermometer, electrical thermometer, liquid-in- metal thermometer, and sonic thermometer.
See also thermograph.
Middleton, W. E. K., and A. F. Spilhaus 1953. Meteorological Instruments. 3d ed., rev., . 67–92.