| 奥 | ào | obscure; mysterious; Austria; Austrian; abbr. for 奥地利; Olympic; Olympics; abbr. for 奥林匹克 |
| 奥地利 | Ào dì lì | Austria |
| 奥秘 | ào mì | secret; mystery |
| 奥运会 | Ào yùn huì | abbr. for 奥林匹克运动会; Olympic Games; the Olympics |
| 奥妙 | ào miào | subtle |
| 奥丁 | Ào dīng | Odin (god in Norse mythology) |
| 奥丁谐振器 | Ào dīng xié zhèn qì | Oudin coil; Oudin resonator |
| 奥什 | Ào shí | Osh (city in Kyrgyzstan) |
| 奥克拉荷马州 | Ào kè lā hé mǎ zhōu | Oklahoma |
| 奥克斯纳德 | Ào kè sī nà dé | Oxnard, California |
| 奥克苏斯河 | Ào kè sū sī Hé | Oxus River; alternative name for Amu Darya 阿姆河 |
| 奥克兰 | Ào kè lán | Auckland (New Zealand city); Oakland (California, US city) |
| 奥切诺斯 | Ào qiē nuò sī | Oceanus, Titan God of the seas before Poseidon |
| 奥利奥 | Ào lì ào | Oreo cookies |
| 奥利安 | Ào lì ān | Orion (constellation, loan word); also written 猎户座 |
| 奥匈帝国 | Ào Xiōng dì guó | Austro-Hungarian empire 1867-1918 |
| 奥古斯都 | Ào gǔ sī dū | Augustus (name) |
| 奥国 | Ào guó | Austria |
| 奥塞梯 | Ào sè tī | Ossetia (a Caucasian republic) |
| 奥塞罗 | Ào sāi luó | Othello, 1604 tragedy by William Shakespeare 莎士比亚 |
| 奥姆真理教 | ào mǔ zhēn lǐ jiào | Aum Shinrikyo, the Japanese death cult responsible for the 1995 sarin gas attack on the Tokyo subway |
| 奥委会 | Ào wěi huì | Olympic committee |
| 奥威尔 | Ào wēi ěr | Orwell (name); George Orwell (1903-1950), British novelist, author of Animal farm 动物农场 and 1984 一九八四年 |
| 奥密克戎 | ào mì kè róng | omicron (Greek letter) |
| 奥巴马 | Ào bā mǎ | Barack Obama (1961-), US Democrat politician, Senator for Illinois from 2005, president from 2009 |
| 奥布里 | Ào bù lǐ | Aubrey (name) |
| 奥康内尔 | Ào kāng nèi ěr | O'Connell (name); Daniel O'Connell (1775-1847), Irish nationalist and catholic activist |
| 奥康纳 | Ào kāng nà | O'Connor (name); Thomas Power O'Connor (1848-1929), Irish journalist and nationalist political leader |
| 奥德修斯 | Ào dé xiū sī | Odysseus |
| 奥德赛 | Ào dé sài | Homer's Odyssey |
| 奥托 | Ào tuō | Otto |
| 奥斯丁 | Ào sī dīng | Austin or Austen (name); Austin, Texas; also written 奧斯汀 |
| 奥斯卡 | Ào sī kǎ | Oscar, The Academy of Motion Picture Arts and Sciences annual award; CL:届 |
| 奥斯卡金像奖 | Ào sī kǎ jīn xiàng jiǎng | Academy Awards; Oscars; CL:届 |
| 奥斯威辛 | Ào sī wēi xīn | Auschwitz (concentration camp) |
| 奥斯威辛集中营 | Ào sī wēi xīn jí zhōng yíng | Auschwitz concentration camp |
| 奥斯曼 | Ào sī màn | Ottoman (empire) |
| 奥斯曼帝国 | Ào sī màn dì guó | the Ottoman empire |
| 奥斯汀 | Ào sī tīng | Austin or Austen (name); Austin, Texas |
| 奥斯瓦尔德 | Ào sī wǎ ěr dé | Oswald |
| 奥斯陆 | Ào sī lù | Oslo, capital of Norway |
| 奥林匹亚 | Ào lín pǐ yà | Olympia (Greece) |
| 奥林匹克 | Ào lín pǐ kè | Olympic |
| 奥林匹克精神 | Ào lín pǐ kè jīng shén | Olympic spirit |
| 奥林匹克运动会 | Ào lín pǐ kè yùn dòng huì | Olympic Games; the Olympics |
奥林匹克运动会组
织委员会 | Ào lín pǐ kè yùn dòng huì zǔ zhī wěi yuán huì | Olympic organizing committee; abbr. to 奥组委 |
| 奥林匹克体育场 | Ào lín pǐ kè tǐ yù chǎng | Olympic Stadium |
| 奥尔巴尼 | Ào ěr bā ní | Albany, New York |
| 奥尔布赖特 | Ào ěr bù lài tè | (Madeleine) Albright (US Secretary of State) |
| 奥尔德尼岛 | Ào ěr dé ní dǎo | Alderney (Channel Islands) |
