joule

The SI (Système Internationale) unit of energy; used to express energy content of foods and energy expenditure; 4.2 kilojoules (kJ) is equivalent to 1 kilocalorie (kcal). Named after James Prescott Joule (1818-1889), British physicist, who determined the equivalence of heat and energy, and the mechanical equivalent of heat.

The SI unit of energy, being the work done by a force of 1 newton acting over a distance of 1 meter. Symbol J.