ˈklapāˌrōn-, -rän- noun
or clapeyron's equation
Usage: usually capitalized C
Etymology: after B.P.E. Clapeyron died 1864 French physicist
: an equation relating to change of phase in a pure substance (as vaporization of a liquid) that gives the rate of change with temperature of the pressure at equilibrium between the phases in terms of the heat of transition and the volumes of the phases before and after the transition — compare clausius-clapeyron equation