An encyclopedia is a book — or a set of books, or, these days, a website or an old CD — that tries to gather facts on many subjects, or to go very deep on one. The old Greek idea was a “circle of education”: the round of learning a young person was meant to complete.

An encyclopediaencyclopedia is a book是一本書 — or a set of books或一整套書, or, these days, a website or an old CD或現在也可能是一個網站或一片舊光碟 — that tries to gather facts on many subjects, or to go very deep on one想把很多主題的資訊都蒐集起來，或是把一個主題講得非常深入。The old Greek idea was古希臘的原意是 a "circle of education""教育的一圈"（circle of education）: the round of learning a young person was meant to complete也就是一個年輕人應該要走完的一整圈學習。

Printed sets with many books used to stand in libraries and in some homes; older people still picture those heavy volumes. Younger people mostly meet the idea online.

Printed sets with many books過去一整套印刷成書的百科全書 used to stand in libraries and in some homes以前常擺在圖書館和一些人家裡; older people still picture those heavy volumes年紀比較大的人腦中還記得那些厚重的一冊冊書。Younger people mostly meet the idea online年輕人大多是在網路上認識這個概念的。

Though actually, no encyclopedia holds “all knowledge”; it holds what its makers chose, in the order they chose, and a paper one stays as it was printed, while a living website can change tomorrow.

Though actually不過其實, no encyclopedia holds "all knowledge"沒有一本百科全書真的裝得下「所有知識」; it holds what its makers chose它裝的是編者選擇要放的東西, in the order they chose用他們選的順序放, and a paper one stays as it was printed而紙本一旦印出來就固定不變了, while a living website can change tomorrow但一個還在更新的網站明天就可能不一樣了。

British spelling often keeps an extra a: encyclopaedia. Same word, not a different thing.

British spelling often keeps an extra a英式拼法通常會多一個a: encyclopaediaencyclopaedia。Same word同一個字, not a different thing不是另一個不同的東西。