fermi; femtometer
A unit of length equal to 10⁻¹⁵ meters, used in nuclear and particle physics. Named after Enrico Fermi.
See also: フェムトメートル
The radius of an atomic nucleus is on the order of a few fermis.
One fermi is equal to 10 to the power of minus 15 meters.
From Italian 'Fermi', after physicist Enrico Fermi. The unit name was adopted internationally and borrowed into Japanese as フェルミ.