The centimetre is a unit of length and is a multiple of the metre; an SI derived unit. It has the symbol cm.
A centimetre is equal to 0.01m. It is also ≈ 0.3937in.
Centimetres are used in maps to scale up conversions to real world measurements.
The fermis is a unit of length in the non-SI metric system and uses the symbol fm.
One fermi is equal to 1×10−15m or 3.9370×10−14 in.
It is used to measure nuclear distances and was named after the Italian physicist Enrico Fermi (1901–1954). It has now been replaced with the SI-derived term femtometre.