noun
or carnot's principle
Usage: usually capitalized C
Etymology: translation of French principe de Carnot, after N.L.S. Carnot, its formulator
: a principle in thermodynamics: an engine working in a reversible cycle is at least as efficient as any other engine working between the same limits of temperature, the efficiency of such an engine being a function of the two limiting temperatures and not dependent on the mechanical design or the working substance of the engine