A system of physical units based on the use of the centimeter, the gram, and the second as elementary quantities of length, mass, and time, respectively. In this system, density is expressed in gm cm−3, speed in cm s−1, force in dynes (gm cm s−2, pressure in baryes (dynes cm−2), and energy in ergs (gm cm2s−2). While this is a popular system of units in nearly all fields of science and technology, some of the meter–kilogram–second system units are more convenient for certain meteorological applications.