Millimeter (noun)

1. A unit of length equal to one thousandth of a meter (0.001 m).
2. A metric unit of length equal to one thousandth of a meter.

Origin:

From milli- + meter.

Examples:

1. The thickness of the sheet of paper is 0.1 millimeters.
2. The length of the object is 2 millimeters.
3. The millimeter is a small unit of length.
4. The measurements were taken in millimeters.
5. The millimeter is used in many scientific and technical fields.