미터의 1,000분의 1에 해당하는 길이의 미터법 단위.
A metric unit of length equal to one thousandth of a meter.
예문:
"The thickness of the credit card is approximately one millimeter."
"The engineer measured the gap with a precision of a fraction of a millimeter."
"Rainfall is often measured in millimeters to indicate the depth of water."