M

is the thirteenth letter of the English alphabet, and represents a labial articulation. As the closure of the lips by which it is formed is accompanied with a humming sound through the nose, it is called the labial nasal. This humming sound distinguishes this letter from b, the position of the lips being the same for both. See Principles of Pronunciation, § 80.—(Print.) A quadrate, the face or top of which is a perfect square. This square is the unit of measurement for the size of type used: 500 m’s of pica would be a piece of matter whose length and breadth in m’s multiplied together produce that number. [Written also em.] (Law.) M is a brand or stigma impressed on one convicted of manslaughter, and admitted to the benefit of clergy.