The millimetre (SI symbol: mm; international spelling) or millimeter (American spelling) is a unit of length in the International System of Units (SI), equal to one thousandth of a metre, the SI base unit of length.

The meaning of MILLIMETER is a unit of length equal to 1/1000 meter.

A millimeter can be defined as a metric unit used to measure the length of small or tiny objects such as measuring lines, the length of a pencil tip, etc. The word is usually expressed as 'mm' and is …

Oct 30, 2025 · A millimeter (mm) is a unit of measurement. It forms part of the metric system and, although this isn’t the dominant system in the US, you’ll likely use mm units a lot.

metric system, international decimal system of weights and measures, based on the metre for length and the kilogram for mass, that was adopted in France in 1795 and is now used officially in almost all …

(abbreviation mm) Add to word list a unit of measurement of length equal to 0.001 meter (Definition of millimeter from the Cambridge Academic Content Dictionary © Cambridge University Press)

A millimeter is a unit of length in the metric system, represented by the symbol "mm". The prefix "milli" derives from the Latin word "mille," meaning one-thousandth.