| n. | 1. | (Print.) The portion of a line formerly occupied by the letter m, then a square type, used as a unit by which to measure the amount of printed matter on a page; the square of the body of a type. |
| Noun | 1. | em - the square of a body of any size of type |
| 2. | em - a linear unit (1/6 inch) used in printing |
| EM - End of Medium |