(n) open investment trust
(n) auberge (French-style inn and restaurant) (fre:)
(n) Ohm's law
(n) (obsc) oral pill (i.e. oral contraceptive pill)
(n) all-star (cast)
(n) oldie
(n) Oort cloud
(n) Old Parr
(n) (sens) old maid (wasei: old miss)
(n) all-night
(P)
(n) totally naked (wasei: all nude)
buck naked
(n) swept back hair (wasei: all back)
(n) aurochs
urus (extinct ancestor of the modern cow, Bos taurus)
(n) eugenol
(n) euthanasia (ger: Euthanasie)
(n) oil color
oil colour
(n) oil dollar
(n) oil ball
(n) oil money
(n) oil road
(n) own goal (soccer)
(n) (abbr) occult culture
(n) oxidase
(n) (hydrogen) peroxide (solution) (ger: Oxydol)
(n) October
(n) Othello (board game) (wasei: Othello game)
(n) ozone hole
(P)
(n) op art
optical art
(n) odometer
(n) onomatopoeia (fre: onomatopee)