從已知線索引出的結論
引走的不是錢，而是一個結論：從手上已經確定的事實往下推。
reasoning · noun · C1
the process of using facts you already know to understand something or form an opinion, or the opinion that you form.
推論；推理
核心畫面
This one noun covers two things that look unrelated: money taken off a total, and a conclusion drawn from what you already know. The link is in the older picture behind the word — leading something down or away from a bigger thing. Lead an amount away from a total and you have a deduction on a ; lead a conclusion down from facts you already hold and you have Sherlock Holmes.
這一個名詞裝著兩件看起來毫不相干的事：從總額裡扣掉的錢，以及從已知的事實推出來的結論。兩者的接點可以想成這個字背後那…更多收起
這一個名詞裝著兩件看起來毫不相干的事：從總額裡扣掉的錢，以及從已知的事實推出來的結論。兩者的接點可以想成這個字背後那個比較老的畫面——「把某樣東西從一個更大的東西那裡引下來、帶走」。把一筆錢從總額引走，就是薪資單上的扣除額；把一個結論從你手上的線索引下來，那就是福爾摩斯在做的事。From the word’s history
Deduction comes from Latin deducere 'to lead or bring away or down' (de- 'down' + ducere 'to lead'). By the mid-15th century it meant 'a taking away, an amount subtracted'; around the 1520s it was taken up in logic for 'derivation as a result from a known principle, an inference'. Both senses keep the same picture of leading something down from a larger whole.
deduction 來自拉丁文 deducere「往下帶、帶走」（de-「向下」＋ ducere「帶領」）。十五世紀中葉，它指的是「拿走、被減去的數額」；到 1520 年代前後，邏輯學借用它來指「從已知原則推導出的結論」。兩個意思保留的是同一個畫面：從一個更大的整體那裡，把某樣東西引下來。
Online Etymology Dictionary (etymonline.com), entry "deduction"
From the picture
Also in this word
amount subtracted · noun · C1
An amount taken away from a total, or the act of taking it away.
扣除；扣除額
原始詞典資料5 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
deductionnoun/dɪˈdʌkʃən/
- 1
That which is deducted; that which is subtracted or removed.
- Near-synonyms: extract, reduction; see also Thesaurus:decrement
- 2
That which is deducted; that which is subtracted or removed.
- standard deduction
- You might want to donate the old junk and just take the deduction.
- 3
businessfinancelawThat which is deducted; that which is subtracted or removed.
- 4
human-scienceslogicmathematicsA process of reasoning that moves from the general to the specific, in which a conclusion follows necessarily from the premises presented, so that the conclusion cannot be false if the premises are true.
- He arrived at the deduction that the butler didn't do it.
- An unkinder deduction, considering only the Select Committee's report and discounting rumours of wayward conclusions by the Stedeford Group, would be that if one inquisition doesn't produce the desired answers, the Minister's policy is "try, try again"—or should one say "fight, fight, fight again".
- 5
human-scienceslogicmathematicsA process of reasoning that moves from the general to the specific, in which a conclusion follows necessarily from the premises presented, so that the conclusion cannot be false if the premises are true.
- Through his powers of deduction, he realized that the plan would never work.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。