Obligatory finesse Odd-even discard signals Oden rule Offside double Ogust rebids One diamond negative response to one club One Notrump opening One Notrump rebid One Notrump response One Notrump response to major, forcing One Notrump response to minor suit One-over-one response One-two-three pre-emptive Openers rebid Opening leads Opening one notrump bid Opponents suit Optional double Out on a limb Out-of-the-blue cuebid Overcall in opponents major suit Overcall in opponents minor suit Overcalls Overlead Overruff Overtake Overtrump
