Femtometre

The femtometre (American spelling femtometer) symbol fm derived from the Danish and Norwegian word femten, "fifteen" (15), Ancient Greek: μέτρον, metrοn, "unit of measurement") is an SI unit of length equal to 10−15 metres, which means a quadrillionth of one. This distance can also be called a fermi and was so named in honour of Italian-American physicist Enrico Fermi, as it is a typical length-scale of nuclear physics.

Femtometre

The femtometre (American spelling femtometer) symbol fm derived from the Danish and Norwegian word femten, "fifteen" (15), Ancient Greek: μέτρον, metrοn, "unit of measurement") is an SI unit of length equal to 10−15 metres, which means a quadrillionth of one. This distance can also be called a fermi and was so named in honour of Italian-American physicist Enrico Fermi, as it is a typical length-scale of nuclear physics.