オ

towel

neon (Ne)

video (esp. a televised image)

radio

timidly

organ (musical instrument)

orange (fruit, colour)

script

studio

stereo (sound)

period (esp. in European languages)

Olympics

violin

champion

opening (a new store, golf course, runway, etc.)

motorcycle

ideology

orchestra

video tape

automation

orchestra

operation

neo

ion

okra (Abelmoschus esculentus)

ozone

otaku

Ottawa (Canada)

opera

organizer

ounce

chaos

oil

trio

bio-

viola

polio

rodeo

ocarina (type of flute)

occult

onion (Allium cepa)

Ohio

off-the-record

operetta

omelette

oracle

(being) on air

Orion

oasis

Galileo

kiosk

kickoff

neo-Nazi

million

union

lion (Panthera leo)

ravioli

(temporary) layoff

Oklahoma

Oceania

opinion

offside

omnibus

oratorio

Orient

original

online

chameleon

Gregorian (calendar)

con brio

Zionist

Zionism

Napoleon

pioneer

pavilion

Oriental

ombudsman

promotional model (at a trade show, etc.)

cohabitation

stereotype

rental video

Orientalism

option

quality

fellatio

Oedipus

oil fence

office

objet d'art

patio

violinist

patriotism

duo

karaoke

oak

auto

ode

aura

all

ogre

oaks

order

Oscar

official

only

owner (esp. of a business)

overcoat

oven

oboe

aurora

quart

KO

theory

octave

off-road

paper-thin wafer (for wrapping powdered medicine, candies, etc.)

oligomer

music box

automatic lock

hors d'oeuvre

creole

diode

play-off

leotard

orthodox

automatic

ozone hole

off-season

observer

operator

display

overlap

overrunning (the base)

opening

open-top car

open set

all-night

creosote

off-season

Belgrade (Serbia)

made-to-order (esp. clothing)

orangutan (Pongo pygmaeus)

overheating

old guard

all-round

kinesiology

cooling-off (period)

million seller

lead-off man

scriptwriter