M.B., Musicæ Baccalaureus=Bachelor of Music.
M.C. Member of Congress; Master of Ceremonies; Member of Council.
M.C.C. Member of the County Council; Marylebone Cricket Club.
M.C.P. Member of the College of Preceptors.
M.C.S. Madras Civil Service.
Md. Maryland.
M.D., Medicinæ Doctor=Doctor of Medicine.
Mdlle., Mlle., Mademoiselle (Fr.). Miss.
Mdm. Madam.
M.E. Most Excellent; Methodist Episcopal; Middle English; Mining Engineer.