The Thirteenth Letter — M
From the very beginning, the pictographic root of the symbol ‘M’ has been obvious. It was Egyptian for water, and the “wave” pictograph continued on through the Sinai and Semitic alphabets. Another competing theory is that it started out as the hieratic symbol for “owl.” Owl or Water, the Phoenicians borrowed the character and it was called mem. The Greeks changed it to “mu.” The straight lines began to curve in the third or fourth century AD. The letterform was in danger of being dropped during the Medieval period because scribes had developed the practice of place a stroke over the letter preceding the “m.” and not drawing the “M.” So Exemplum would be Ex¯eplu¯
The “M” is one of the widest of all letters, its width being very nearly its height. The angle and depth of the “V” can vary from typestyle to typestyle. The key to drawing the letter effectively is that the side strokes really must appear to support the rest of the letterform. In typography the size of a fixed space is called an “em-space,” or the width of the letter “M” in that particular font style.