Micri-
Micri- is an archaic non-SI decimal metric prefix for 10−14. Its symbol is mc.
It was proposed as a prefix for the CGS-unit of energy, the erg. The name micri-erg was proposed in 1922 by William Draper Harkins as a unit of energy equating to 10−14 erg, the equivalent to 10−21 joule, as a convenient unit to measure the surface energy of molecules in surface chemistry. It only saw limited use. In 1991, the micrierg was officially designated the zeptojoule when the zepto-prefix for 10−21 was officially adopted.
