O字開頭的單詞或詞組
operating systemorchestrateon guardornamentover-the-counteron-the-joboutgrownopusOmanobliviousorientalon and offorthodoxone after anotherOct.overtureovertoutbreakoccultopposedobsidianoverheardohoorphanageOxfordourson dutyonceoff-limitsotorhinolaryngologyocteton arrivaloutdoorsoutcomeOklahomaotteroverchargeOphidiaobjectivenessoverhaulonyxone-off