American English to British English: Letter O
Oarlock Rowlock
Oatmeal Porridge
Ocher Ochre
Octillion AE n+27 Octillion BE n+48 zeros
Octodecillion AE n+57 zeros Octodecillion BE n+108 zeros
Odometer Mileometer
Odor Odour
Off-ramp Exit ramp
Offense Offence
Offenseless Offenceless
Office/practice (doctor’s/dentist’s ~) Surgery (doctor’s/dentist’s ~)
Oil pan Sump
Oilcloth American cloth
Omelet Omelette
On (Americans live on a street) In (Britons live in a street)
On (weekends/the weekend) At (weekends/the weekend)
On sale On offer
On/over (the weekend) At (the weekend)
One way (ticket) Single (ticket)
One-time (adj.) One-off (adj.)
One/Oneself (not widely used in US) One/Oneself
Op Ed page Leader & opinion page
Operating room Operating theatre
Optimize Optimise
Optometrist Optrician
Orchestra Stalls
Organization Organisation
Organize Organise
Organizers Organisers
Orient (v.) Orientate (v.)
Oriented Orientated
Orthopedics Orthopaedics
Ostracize Ostracise
Outage (power) Blackout (power)
Outmaneuver Outmanoeuvre
Overalls Dungarees
Overalls Overalls/Dungerees
Overhead bins Overhead lockers
Overpass Flyover
Oxidize Oxidise
Have I missed anything? Send in your American/British differences now.
