British English and American English - M, N, O

British English	American English
mackintosh	raincoat
mad	crazy, insane
main road	highway
maize	corn
managing director	CEO (chief executive officer)
mangetout	snow pea
market garden	truck farm
marshalling yard	railroad yard
marvellous	marvelous
mashed potato	mashed potatoes
match	game
maths	math
medallist	medalist
metalled road	paved road
metre	meter
millimetre	millimeter
milometer	odometer
mineral water	bottled water
minim  (music)	half note
mobile phone, mobile	cell phone
moderator	mediator
monkey tricks	monkeyshines
motorbike	motorcycle
motorway	highway, freeway, expressway, interstate highway, interstate
mum/mummy	mom/mommy
nappy	diaper
national insurance number	social security number
naughts and crosses	tic-tack-toe
needlecord	pinwale
neighbour	neighbor
newsreader	newscaster
note	bill
notice board	bulletin board
noughts and crosses	tic-tac-toe
number plate	license plate
odour	odor
offence	offense
off-licence	liquor store; package store
opencast mining	open-pit mining
ordinary share	common stock
oven glove	oven mitt