millimeter, mm

Abbreviated mm, no period.

In text, usually spelled out as a noun or adjective, although may be abbreviated as an adjective in some

standard uses:

            a caterpillar 25 millimeters long

            a 10-millimeter-wide line

but     16-mm film

            7.7-mm shell

In photographic data, film and lens sizes are often written without a hyphen:

            35mm film

            200mm zoom

Either style is accepted as long as it is consistent.

See also kilometer, km, meter, m, centimeter, cm, METRIC AND INTERNATIONAL MEASUREMENT.