1. Plural of millimetre; units of length equal to one thousandth of a metre, or approximately 0.039 inches.
Usage: British English spelling; American English uses 'millimeters'; Commonly abbreviated as 'mm'

Examples

• The thickness of the paper is 0.1 millimetres.
• The engineer measured the gap in millimetres to ensure precision.
• A grain of sand is typically between 0.1 and 2 millimetres in diameter.
• The ruler shows measurements in both centimetres and millimetres.
• The rainfall was recorded as 5 millimetres for the day.