Millimetres.
mm
The diameter of the bullet casing, measured at 7.3 mm, is 7.3 millimeters.
mm
In USA it is measured in inches, in. In other countries it is measured in millimetres, mm.
No, it is measured by weight in milligrams ( mg) not by mm which is volume.
In millimeters (mm)
There is no intrinsic fraction for MM. If something is measured as a whole number of MM then it is an integer value, not a fraction.
mm^3
3.8 millimeters
Focal length is measured in milimeters (mm) -----------------------------------------------------------------
milimeters
cubic centimeter