centimetre

The centimetre (cm; American spelling centimeter) is a unit of length in the metric system. It is defined as one hundredth of a metre, so 1 cm = 0.01 m and 1 m = 100 cm. It is a derived unit and is accepted for use with the International System of Units (SI), though it is not itself an SI base unit. A common related unit is the millimetre (mm), with 10 mm = 1 cm.

Etymology and usage: The name comes from centi-, meaning hundred, and metre. Centimetres are widely used in everyday measurements, including body height, clothing sizes, the dimensions of small objects, and display and screen sizes.

Conversions and examples: In customary units, 1 inch equals 2.54 cm, and 1 foot equals 30.48 cm. A typical credit card is about 8.5 cm wide. In scientific contexts, lengths are often quoted in metres or millimetres, with centimetres used for convenience in many engineering and architectural measurements.

Tools and standards: Measuring devices such as rulers and tape measures are commonly marked in centimetres and millimetres. For higher precision, instruments like vernier calipers or micrometers are used. The metre, and thus the centimetre derived from it, is governed by the International Bureau of Weights and Measures (BIPM) and defined by international agreements.