A centimetre (American spelling: centimeter, symbol cm) is a unit of length in the metric system, equal to one hundredth of a metre, which is the current SI base unit of length. Centi is the SI prefix for a factor of 10 − 2.] Hence a centimetre can be written as 10×10 − 3 m (engineering notation) or 1 E-2 m (scientific E notation) — meaning 10 × 1 mm or 1 m / 100 respectively. The centimetre is the base unit of length in the now deprecated centimetre-gram-second system of units.
Though for many physical quantities, SI prefixes for factors of 103 - like milli and kilo - are often preferred by technicians, the centimetre remains a practical unit of length for many everyday measurements. A centimetre is approximately the width of the fingernail of an adult person.
What is a Meter?
(from Wikipedia)
The metre or meter (symbol: m) is the fundamental unit of length in the International System of Units (the SI). It was originally defined so that the land distance between Earth's poles and Equator would be exactly 10,000,000 metres; today, the way it is defined means the speed of light is exactly 299,792,458 metres per second.
Because it is the unit of length in the SI, all SI units that involve length (such as area or speed) are defined in terms of the metre, as are vectors.
As with all metric units, decimal multiples and submultiples of the metre— such as kilometre (1,000 metres) and centimetre (0.01 metres)— can be formed by adding SI prefixes to its name or symbol.
