The thermal state of a body considered with reference to its ability to communicate heat to other bodies (J. C. Maxwell). There is a distinction between temperature and heat, as is evidenced by Helmholtz's definition of heat as “energy that is transferred from one body to another by a thermal process,” whereby a thermal process is meant radiation, conduction, and/or convection. Temperature is measured by such instruments as thermometers, pyrometers, thermocouples, etc., and by scales such as centigrade (Celsius), Fahrenheit, Rankine, Reaumur, and absolute (Kelvin).See Absolute Temperature; Thermodynamics.