1. (

• femtometer ,
• femtometre ,
• fermi

) a metric unit of length equal to one quadrillionth of a meter ;

2. (

• Fermi ,
• Enrico_Fermi

) Italian nuclear physicist (in the United States after 1939) who worked on artificial radioactivity caused by neutron bombardment and who headed the group that in 1942 produced the first controlled nuclear reaction (1901-1954) ;