| M. | Male; Martyr; Master; mate; men; Methodist; Monsieur (French), Mr.; one thousand (Roman). |
| m. | Maiden(-s) (cricket); married; masculine; metre(-s); mile(-s); mill; minim; minor; minute(-s); month(-s); mother. |
| ma. | Major (older). |
| m/a. | My account. |
| Macc. | Book of Maccabees. |
| mach. | Machinery. |
| mag. | Magazine; magnetic magneto magnitude; magnum. |
| Mal. | Book of Malachi. |
| Man. | Manitoba. |
| man. | Manual; manufacture(-d). |
| M & B 693. | May and Baker sulphonamide. |
| Mar. | March. |
| mar. | Married; maritime. |
| marg. | Marginal. |
| Mat. | Gospel of S. Matthew; matinee; Matins. |
| max. | Maxim; maximum. |
| M.C. | Master of ceremonies. |
| M/C(r). | Manchester. |
| Md. | Maryland. |
| M.D. | Mentally deficient; Middle Dutch. |
| m.d. | Month's date. |
| Me. | Maine. |
| M.E. | Marine engineer; Middle East; Middle English. |
| mech. | Mechanical. |
| Med. | Medical; medieval; Mediterranean; medium. |
| mem. | Memento; memorandum; memorial. |
| Mer. | Merionethshire. |
| mer. | Meridian. |
| Mess. | Messenger. |
| Messrs. | Messieurs (French), Sirs. |
| Met. | Metallurgical; metaphysica1; meteorology; metronome; metropolitan; Metropolitan Railway. |
| Meth. | Methodist. |
| meth. | Methylated spirit. |
| mf. | Mezzo forte (Italian), moderately loud. |
| m.f. | More follows. |
| mfd. | Manufactured. |
| mfg. | Manufacturing. |
| M.F.H. | Master of Foxhounds. |
| M.F.N. | Most favoured nation. |
| M.Fr. | Middle French. |
| mir. | Manufacturer. |
| mg. | Milligramme(-s). |
| M.G.M. | Metro - Goldwyn -Mayer. |
| M.H.G. | Middle High German. |
| M.I. | Medica1 inspection; Military intelligence. |
| mi. | Minor (younger). |
| Mic. | Book of Micah. |
| Mich. | Michigan. |
| Middx. | Middlesex. |
| mil. | Military; milreis. |
| Min. | Minister; Ministry; minster. |
| mm. | Mineral; minim; minimum; minimus (youngest); minute. |
| Minn. | Minnesota. |
| Miss. | Mississippi. |
| M.It. | Middle Italian. |
| mkt. | Market. |
| M.L. | Medieval Latin. |
| ml. | Millilitre(-s). |
| M.L.G. | Middle Low German. |
| Mile., Mdlle. | Mademoiselle (French), Miss. |
| MM. | Martyrs; Messieurs (French), Sirs. |
| M.M. | Maelzel's metronome; Messageries Maritimes (French shipping company). |
| mm. | Millimetre(-s). |
| m.m. | Mutatis mutandis (Latin), the necessary changes being made. |
| Mme. | Madame. |
| M.N. | Merchant Navy. |
| Mo. | Missouri. |
| M.O. | Manually operated; Medical Officer; money order. |
| mo. | Month. |
| mod. | Moderate; modern. |
| Mods. | Moderations. |
| M.O.H. | Master of Otterhounds; Medical Officer of Health; Ministry or Health. |
| M.O.I. | Ministry of Information. |
| Mon. | Monastery; Monday; Monmouthshire. |
| mon. | Monetary. |
| Mons. | Monsieur (French), Mr. (incorrect abbrev.). |
| Mont. | Montana; Montgomeryshire. |
| M.O.O. | Money order office. |
| Mort. | Mortgage. |
| M.P. | Member of Parliament; Metropolitan Police; Military Police. |
| mp. | Mezzo piano (Italian), moderately soft. |
| M. Pen. | Ministry of Pensions. |
| m.p.g. | Miles per gallon. |
| m.p.h. | Miles per hour. |
| M.P.O. | Metropolitan Police office. |
| Mr. | Mister. |
| M.R. | Map reference; Maria Regina (Latin), Queen Mary; Municipal Reform. |
| Mrs. | Mistress (married woman). |
| MS(-S). | Manuscript(-s). |
| M.S. | Motor ship. |
| M.S.H. | Master of Staghounds. |
| M.S.L. | Mean sea level. |
| M.T. | Means test; mechanical transport; Ministry of Transport. |
| mt(-s). | Mount or mountain(-s). |
| mtd. | Mounted. |
| mun., munie. | Municipal. |
| mus. | Museum; musical. |
| M.V. | Merchant vessel; motor vessel. |
| M.Y. | Motor yacht. |