The decimetre (International spelling as used by the International Bureau of Weights and Measures; SI symbol dm) or decimeter (American spelling) is a unit of length in the metric system, equal to one tenth of a metre, the SI base unit of length (or ten centimetres). Equivalently, there are 10 decimetres in a metre. It can be written in scientific notation as 100×10−3 m (engineering notation) or 1 E-1 m (exponential notation) — meaning 100 × 1 mm or 0.1 m respectively. The c is pronounced as /s/, unlike in decametre. The common non-SI metric unit of volume, the litre, is defined as one cubic decimetre (however, between 1901 and 1964, there was a slight difference between the two due to the litre being defined with respect to the kilogram rather than the metre).