A UFO is something seen in the sky that the person watching cannot identify. That is all the letters actually say — unidentified flying object.

A UFO UFO is指的是 something seen in the sky在天空中被看到的東西 that the person watching cannot identify但看到的人無法辨認的. That這幾個字母 is all the letters actually say其實就只是在講這個 — unidentified flying object unidentified flying object（不明飛行物）.

But in real use the word has drifted a long way from that plain meaning: when people say UFO, most listeners hear 'alien spaceship', and that is usually what the speaker means too. This is why serious writers and government reports have moved to the newer term UAP, unidentified aerial phenomenon, precisely to get away from the spaceship feeling that UFO now carries.

But in real use不過在實際使用中, the word has drifted a long way from that plain meaning這個字已經漂離那個單純的字面意思很遠了: when people say UFO當人們說UFO時, most listeners hear 'alien spaceship'大多數聽的人會聯想到'外星飛船', and that is usually what the speaker means too而通常說話的人講的也正是這個意思. This這 is why serious writers and government reports have moved to the newer term UAP就是為什麼嚴謹的作者和政府報告都改用比較新的說法UAP, unidentified aerial phenomenon（unidentified aerial phenomenon，不明空中現象), precisely to get away from the spaceship feeling that UFO now carries正是為了擺脫UFO現在帶有的那種飛船感.

So the word sits in two places at once. Used carefully, it is honest and modest: I saw something, I do not know what it was. Used the ordinary way, it belongs to films, tabloid newspapers and late-night stories, and it carries a slight smile — call a person a UFO believer and you are half teasing them.

So所以 the word sits in two places at once這個字同時存在於兩個地方. Used carefully小心使用的時候, it是 honest and modest誠實而謙虛的: I saw something, I do not know what it was我看到了某個東西，我不知道那是什麼. Used the ordinary way用一般的方式使用的時候, it它 belongs to films, tabloid newspapers and late-night stories屬於電影、小報和深夜故事的世界, and it carries a slight smile而且帶著一點點笑意 — call a person a UFO believer叫一個人UFO believer（相信幽浮的人）, and you are half teasing them你有一半是在調侃他.

It is a countable noun: one UFO, three UFOs. People say the letters one by one, 'U-F-O', though 'yoo-foh' as a single word exists and sounds more casual or joking.

It它 is a countable noun是可數名詞: one UFO, three UFOsone UFO、three UFOs. People人們 say the letters one by one通常一個字母一個字母唸, 'U-F-O''U-F-O', though 'yoo-foh' as a single word exists and sounds more casual or joking不過把它當一個字唸成'yoo-foh'的說法也存在，聽起來比較隨性或帶點開玩笑的味道.