deduction

deduction 主要有两个常见意思：从金额或总数中扣除的一部分，以及根据已知前提必然推出结论的演绎推理。

💡 记忆钩子

把 deduction 记成“从一个整体中取出一部分”：在金额意义中，是把钱从总数里扣掉；在推理意义中，是从一般规则和已知前提中“取出”一个具体结论。两者概念不同，前者围绕扣除，后者围绕演绎。

📝 学习建议

先掌握“扣除额”这一日常意义，再学习逻辑意义；在税务或账单语境中，deduction 通常不是“推理”。
逻辑意义要注意它和 induction（归纳）相反：deduction 从一般规则走向具体结论，且前提为真时结论必须为真。

📖 中文释义

noun

common 扣除额；扣除

📖 指从总金额、总数或应得数额中减去的一部分，或这个扣除行为本身。常见于税款、工资、费用和账目计算。

💡 常见结构是 “a deduction from + 金额或总数” 或 “a tax deduction”，也可说 “make a deduction”。表示具体被扣掉的一项时通常用可数形式；泛指扣除这一做法时可用不可数形式。不要把它误解成额外收费，deduction 是从原有数额中减去。

countable uncountable

The donation qualifies as a tax deduction.

这笔捐款符合税前扣除的条件。
core 演绎推理；演绎出的结论

📖 指从一般规则、事实或前提出发，推出一个具体结论的推理过程；如果前提都是真的，推导出的结论就不能是假的。在日常语境中，也可指通过这种推理得出的判断。

💡 常见结构是 “make/draw a deduction” 或 “the deduction that + 从句”，也可用 “by deduction” 表示通过演绎推理。这个词在逻辑、哲学、数学和较正式的分析语境中尤其常见。不要把它和仅凭线索作出的猜测混同，演绎推理需要能支撑结论的明确前提。

countable uncountable

From these facts, we can make the deduction that the door was locked from inside.

根据这些事实，我们可以推断出门是从里面锁上的。

Her deduction was based on a simple rule and two reliable facts.

她的演绎结论建立在一条简单规则和两个可靠事实之上。

deductions plural

📘 英文释义 (WordNet) 共 6 组

the act of subtracting (removing a part from the whole)

同义词集: subtraction deduction

he complained about the subtraction of money from their paychecks

反义: addition 上位: decrease, diminution, reduction, step-down 下位: bite, withholding

the act of reducing the selling price of merchandise

同义词集: discount price reduction deduction

上位: decrease, diminution, reduction, step-down

reasoning from the general to the particular (or from cause to effect)

同义词集: deduction deductive reasoning synthesis

上位: abstract thought, logical thinking, reasoning

something that is inferred (deduced or entailed or implied)

同义词集: deduction entailment implication

his resignation had political implications

上位: illation, inference

an amount or percentage deducted

同义词集: deduction discount

上位: adjustment, allowance

a reduction in the gross amount on which a tax is calculated; reduces taxes by the percentage fixed for the taxpayer's income bracket

同义词集: tax write-off tax deduction deduction

上位: write-down, write-off 下位: exemption

🌳 词源

源自中古法语 déduction，最终源自拉丁语 deductio，与 deduct 和 deduce 同源。

From Middle French déduction, from Latin deductio. Equivalent to deduct + -ion or deduce + -tion.

🔄 变式

deductions plural

🏷 单词标签 & 词根