Never having happened before — or never having happened on this scale. A precedent is an earlier case that shows this kind of thing has happened, so if something is unprecedented, there is no earlier case like it to point back to. Two slightly different uses hide inside that one word.

never having happened before從來沒有發生過——or never having happened on this scale或是從來沒有發生到這種規模。a precedentprecedent（先例） is an earlier case that shows this kind of thing has happened是一個之前發生過的案例，證明這種事情發生過，so if something is unprecedented所以如果某件事是 unprecedented 的，there is no earlier case like it to point back to就代表沒有可以拿來對照的先例。two slightly different uses hide inside that one word這一個字裡面其實藏了兩種稍微不同的用法。

Sometimes it means the event itself is brand new in kind: an unprecedented decision, a country doing something no country has done before. Sometimes the event is ordinary but the size or number is new: unprecedented rain, unprecedented demand, unprecedented numbers of visitors. It rains every year, so the second use is really "more than ever recorded".

sometimes it means the event itself is brand new in kind有時候是指這件事本身就是全新的一種：an unprecedented decision一個 unprecedented 的決定，a country doing something no country has done before一個國家做了從來沒有國家做過的事。sometimes the event is ordinary but the size or number is new有時候這件事本身很平常，但規模或數量是新的：unprecedented rain, unprecedented demand, unprecedented numbers of visitorsunprecedented 的雨量、unprecedented 的需求、unprecedented 的訪客人數。it rains every year雨每年都會下，so the second use is really "more than ever recorded"所以第二種用法其實是「比有紀錄以來都多」。

The word is formal. You meet it constantly in news reports, business talk, and government statements, and almost never between friends — a friend says "I've never seen anything like it".

the word is formal這個字很正式。you meet it constantly in news reports, business talk, and government statements你會在新聞報導、商業談話、政府聲明裡一直碰到它，and almost never between friends但朋友之間幾乎不會這樣講——a friend says "I've never seen anything like it"朋友會說「我從來沒看過這樣的事」。

It is also, honestly, a word people stretch. Journalists and advertisers reach for it because it sounds dramatic, and much of what they call unprecedented turns out to have happened in 1987 or 1953; strictly it should mean nobody has a record of this before, but in practice it often just means "very unusual, very big".

it is also, honestly, a word people stretch老實說，這也是一個人們會用得比較誇張的字。journalists and advertisers reach for it because it sounds dramatic記者和廣告商喜歡用它，因為聽起來很戲劇化，and much of what they call unprecedented turns out to have happened in 1987 or 1953而他們說的很多 unprecedented 其實在 1987 年或 1953 年就發生過了；strictly it should mean nobody has a record of this before嚴格來說它應該是指沒有人有這件事之前發生過的紀錄，but in practice it often just means "very unusual, very big"但實際用起來常常就只是「很不尋常、很大」的意思。

It leans negative — crises, disasters, price rises — though it is not required to; unprecedented growth and unprecedented success are perfectly normal. There is no comparison: something either has a precedent or it does not, so careful writers avoid "more unprecedented", even though you will hear it.

it leans negative — crises, disasters, price rises —它偏向負面的意思——危機、災難、物價上漲——though it is not required to不過不是一定要負面；unprecedented growth and unprecedented success are perfectly normalunprecedented growth 和 unprecedented success 都是完全正常的用法。there is no comparison這個字沒有比較級：something either has a precedent or it does not一件事要嘛有先例，要嘛沒有，so careful writers avoid "more unprecedented"所以謹慎的作者會避免用「more unprecedented」，even though you will hear it雖然你還是會聽到有人這樣講。