A centimetre (the American spelling is centimeter, symbol cm) is a unit of length in the International System of Units (SI) measurement system. It is equal to one hundredth of a metre. Centi- is placed in front to say 'a hundredth'. The centimetre is the base unit of length in the old centimetre-gram-second (CGS) system of units.
Similarities to other units of length [change]
1 centimetre is equal to:
- 10 millimetres
- 0.01 metre (1 metre is equal to 100 centimetres)
- about 0.393700787401575 inch (1 inch is equal to 2.54 centimetres) 
Uses of centimetre [change]
The centimetre is also used:
- sometimes, to measure how much rain has fallen into by a rain gauge 
- in maps, centimetres are used to change from map scale to real world scale (kilometres)
Unicode symbols [change]
- centimetre (㎝) - code 339D
- square centimetre (㎠) - code 33A0
- cubic centimetre (㎤) - code 33A4
They are placed into one character, and it is mostly used with East Asian fonts.
- Inch - from Eric Weisstein's World of Physics
- Rain Measurement, Rain Gauge, Wireless Rain Gauge, Rain Gage, Rain Gauge Data
-  CJK Compatibility excerpt from The Unicode Standard, Version 4.1.
- CJK Compatibility excerpt from The Unicode Standard, Version 4.4 and co-exterior users.