Monsieur, M., Madame, Mme, Mademoiselle, Mlle

Monsieur is abbreviated M. (use period, exception to Webster's).

Madame is abbreviated Mme (no period).

Mademoiselle is abbreviated Mlle (no period).

In general, do not use these social titles in editorial copy.  Instead, on first use give a person's full name; in subsequent references use only the last name.

See also TITLES OF PERSONS.