A centimetre (American spelling: centimeter, symbol cm)'s a unit of length in the metric system, equal to one hundredth of a metre, which's the current SI base unit of length. Centi's the SI prefix for a factor of . Hence a centimetre can be written as m}} (engineering notation) or (scientific E notation) — meaning mm}} or respectively,centimetre-gram-second system of units. Though for many physical quantities, SI prefixes for factors of 103—like milli- and kilo-—are often pre… (More on Centimeter)