 |  |  |
British | Canadian | American |
M | ||
| macaroni cheese | macaroni and cheese, Kraft dinner | macaroni and cheese |
mac(k), raincoat | raincoat | raincoat |
mad, crazy | crazy | crazy |
main course | entrée, main course | entrée, main course |
main road | main road, highway | highway |
male prostitute, rent boy | male prostitute | male prostitute |
mange-tout | snow peas, sugar peas | snow peas, sugar peas |
manic depression | manic depression, bipolar | manic depression, bipolar |
man of the match | most valuable player | most valuable player |
| marks | marks, grades | grades |
marrow | vegetable marrow | vegetable marrow, gourd |
mashed potato, mash, Smash | mashed potato | mashed potato |
| masking tape | duct tape, masking tape | duct tape, masking tape |
maths | math | math |
| mature (cheese) | mature, sharp, vintage | mature, sharp, vintage |
| mayor | mayor, reeve | mayor |
| merry-go-round, roundabout | carousel, merry-go-round | carousel, merry-go-round |
Mexican wave | wave | wave |
| Middle East | Middle East, Mideast | Middle East, Mideast |
| mileometer | odometer | odometer |
mince, minced beef | ground beef, minced meat | ground beef |
| minor collision (between vehicles) | fender-bender | fender-bender |
mobile home, caravan | trailer, mobile home, motor home, fifth wheel, RV (recreational vehicle) | trailer, mobile home, motor home, fifth wheel, Winnebago |
mobile phone, mobile, moby | cell(ular) phone, mobile phone | cell(ular) phone, mobile phone |
moggie, pussy, cat, pussycat | cat, pussycat | cat, pussycat |
| money, brass, loot, lolly, bread, bunce, dosh, spondulicks, dough, lookah, wonga | money | money |
Monopolies & Mergers Commission, Office of Fair Trading | Competition Tribunal | Federal Trade Commission (FTC) |
| mosquito, mozzie | mosquito, skeeter | mosquito, skeeter |
most successful | most successful | most successful, winningest (sl) |
| Mother's Day, Mothering Sunday | Mother's Day | Mother's Day |
motorbike | motorbike, hog, motorcycle | motorcycle |
motorway | highway, freeway, autoroute (Quebec), superhighway | freeway, expressway, highway, interstate, superhighway |
mountaineer | mountaineer | mountaineer, alpinist |
mouth organ, harmonica | harmonica, mouth organ, mouth harp | harmonica |
| mudguard | fender | fender |
muesli | granola | granola |
| multi-purpose vehicle, MPV, people carrier | minivan | minivan |
| multi-storey car park | parkade, parking garage | parking garage |
mum, mummy | mom, mommy, mum, mummy | mom, mommy, mama |
| mummy's boy | mama's boy | mama's boy |
| Murphy's Law, Sod's Law | Murphy's Law | Murphy's Law |
| Musical Statues | Freeze Dance | Freeze Dance |
P