British English to American English: Letter M
Mack  Rain coat
          Mackintosh  Rain coat
          Mad Crazy
          Made-to-measure Custom made
          Magnetise Magnetize
          Main course Entrée
          Maisonette =  
          Maize Corn
          Managing director md Chief executive officer ceo
          Mange tout Sweetpea/sugarsnap/snowpea
          Manoeuvrable Maneuverable
          Manoeuvrability Maneuverability
          Manoeuvre  Maneuver
          Manoeuvring Maneuvering
          Marginalise Marginalize 
          Marks Points
          Marrow  Squash
          Marvelling Marveling
          Marvellous Marvelous 
          Marvellously Marvelously 
          Marquee Party tent
        Marquess Marquis

          Marshalled Marshaled
          Marshaller Marshaler
          Marshalling Marshaling
          Mashed potato Mashed potatoes 
          Masque Mask 
          Match (football ~) Game (football ~)
          Materialise Materialize
          Maths Math
          Maths problem Math Problem
          Mathematics Mathematics
          Mattins Matin
          Maximise Maximize
          MBA M.B.A.
          Meagre Meager          Meagerness
          Meagrely  Meagerly
          Mean Stingy/Tight with money
          Mechanise Mechanize
          Mediaeval Medieval
          Medivac Medevac
          Medium quarto = size of book format (24x30cm) 91/2 x 12 in  
          Meet With (meet ~)
          Megaphone/loud-hailer Bullhorn
          Mercer =  
          Merry-go-round Carousel
          Memorise  Memorize
          Memorisation Memorization
          Mend Repair
          Mend something Fix something
          Merchant bank  Investment bank
          Mesmerise Mesmerize
          Metabolise Metabolize 
          Meter (measuring device) Meter
          Methylated spirits  Denatured spirits
          Metre (1m) Meter
          Mezzanine (theatre) Dress Circle (theater)
          Microlight (aircraft) Ultralight (aircraft)

          Mileage Milage
          Mile marker Milepost
          Mileometer  Odometer
          Milliard (now billion) n+9 zeros Billion
          Mince (meat)  Hamburger meat/Ground meat
          Mincer  Meat grinder
          Mineral water Soda water
          Miniaturise Miniaturize 
          Mini-cab = taxi that can be ordered but cannot cruise about looking for fares.  
          Minim Half note
          Minimise Minimize
          Minister Preacher
          Minster =  
          Misbehaviour Misbehavior
          Misdemeanour Misdemeanor
          Misjudgement Misjudgment
          Misspell, Misspelt, Misspelt Misspell, Misspelled, Misspelled
          Mitre Miter
          Mobile Cell/cellular
          Mobile phone Cell/cellphone
          Mobilise Mobilize
          Modelled Modeled
          Modeller Modeler
          Modelling Modeling
          Modernise Modernize 
          Mollusc Mollusk
          Moisturise Moisturize
          Momentarily = a brief momen Momentarily = very soon
          Monetise Monetize
          Monologue Monolog
          Monopolise Monopolize 
          Money box = children’s savings tin  
          Moralise Moralize
          Motif Motive
          Motorise Motorize 
          Motorist Driver
          Motorway Freeway (West US)
          Motorway Highway (East US)
          Mould  Mold
          Moulding Molding
          Mouldy Moldy
          Moult Molt
          Moustache  Mustache 
          Mouthorgan Harmonica

          Moveable Movable
          Move house Move
          Mow, mowed, mown Mow, Mowed, Mowed
          Mr Mr.
          Mrs Mrs.
          M.Sc. M.S.
          Mudguard  Fender
          Mum  Mom
          Muesli  Granola
          Music hall Vaudeville
          Muslim Moslem
          Muslin Cheesecloth
          Mystagogue Mystagog
          Mythicise Mythicize
          Mythologise Mythologize 
Have I missed anything? Send in your American/British differences now.


