In thermodynamics, power is defined as energy exchanged between a system and its surroundings per unit time. [1] This is stated formulaically as:

Power, defined another way, is the rate at which work is done or energy transferred. [2]

See also
● Horsepower
● Motive power

References
1. Perrot, Pierre. (1998). A to Z of Thermodynamics, Oxford: Oxford University Press.
2. Daintith, John. (2005). Oxford Dictionary of Physics. Oxford University Press.