mil 1 
(mĭl)
(mĭl)n.
1. A unit of length equal to one thousandth (10-3) of an inch (0.0254 millimeter), used, for example, to specify the diameter of wire or the thickness of materials sold in sheets.
2. A milliliter; one cubic centimeter.
3. A unit of angular measurement used in artillery and equal to 1/6400 of a complete revolution.
[Short for Latin mīllēsimus, thousandth, from mīlle, thousand; see gheslo- in the Appendix of Indo-European roots.]