真的裝置：埋好，等時間到
同一個裝置的兩種材料：一個裝炸藥，一個裝程式碼。
noun · B2
A bomb with a clock or timer inside it, set so that it goes off at a chosen time instead of straight away.
定時炸彈
核心畫面
One way to hold this word: something dangerous is already in place, and nothing is happening yet. That is the whole picture. A clock is running inside it, the hour has been chosen, and until that hour arrives the room looks perfectly ordinary. What makes the word bite is not the damage, which you never see, but the waiting — the gap between how calm it looks now and what is certain to arrive. Every use of the word keeps that gap. Only the thing doing the waiting changes.
可以想成這樣一個畫面：危險的東西已經放好了，而現在什麼事都還沒發生。整個字就是這個畫面。裡面有個鐘在走，時間也早就設…更多收起
可以想成這樣一個畫面：危險的東西已經放好了，而現在什麼事都還沒發生。整個字就是這個畫面。裡面有個鐘在走，時間也早就設定好了，在那一刻到來之前，房間看起來再平常不過。這個字真正咬人的地方不是爆炸——爆炸你根本看不到——而是那段等待：眼前這麼平靜，跟等一下一定會來的事之間，那道落差。這個字的每一種用法都保留了那道落差，換掉的只是「等在那裡的東西」是什麼。From the word’s history
Wiktionary records the word as from time + bomb: a bomb tied to a clock rather than to the moment.
維基詞典把這個字記成 time 加 bomb：一顆綁在鐘上、而不是綁在當下的炸彈。名字本身就已經把「等」寫進去了。
Wiktionary entry for time bomb (etymology_text in the supplied evidence packet): From time + bomb.
Two branches
比喻：現在沒事，但一定會爆
把裝置拿掉，只留下那段等待，用來講一個正在累積的麻煩。
noun · B2
A situation that looks calm now but is very likely to turn into a serious problem later, because whatever causes the problem is already building up.
遲早會爆的問題