Merriam-Webster Collegiate Dictionary - mil

 I. noun  Etymology: Latin ~le thousand  Date: 1721  1. thousand found a salinity of 38.4 per ~  2. a monetary unit formerly used in Cyprus equal to 1/1000 pound  3. a unit of length equal to 1/1000 inch used especially in measuring thickness (as of plastic films)  4. a unit of angular measurement equal to {frac1/6400} of 360 degrees and used especially in artillery  II. noun  or ~l  (plural ~ or ~l)  Etymology: short for ~lion  Date: circa 1942 slang a ~lion dollars  III. abbreviation ~itary