Erg \Erg\, n. [Gr. ? work.] (Physics) The unit of work or energy in the C. G. S. system, being the amount of work done by a dyne working through a distance of one centimeter; the amount of energy expended in moving a body one centimeter against a force of one dyne (981 dynes exert the same force as a one gram mass in the earth's gravitational field). One foot pound is equal to 13,560,000 ergs. The absolute Joule is equivalent to 10^{7} ergs, which are equivalent to 0.2389 gram-calories at 15[deg] C. See also {mechanical equivalent of heat} under {equivalent}. [1913 Webster +PJC]