A coefficient that determines the rate of change of some physical property with change in temperature. For example, the dependence of the resistance (R) of a material on the Celsius temperature t, is given by R =R₀ + α‎t + β‎t², where R₀ is the resistance at 0°C and α‎ and β‎ are constants. If β‎ is negligible, then α‎ is the temperature coefficient of resistance.