Webster's Revised Unabridged Dictionary · 1913

Deduction

Deduction , noun

[Latin deductio: compare French déduction.]

1.
Act or process of deducing or inferring.
The deduction of one language from another. — Johnson
This process, by which from two statements we deduce a third, is called deduction. — J. R. Seely
2.
Act of deducting or taking away; subtraction; as, the deduction of the subtrahend from the minuend.
3.
That which is deduced or drawn from premises by a process of reasoning; an inference; a conclusion.
Make fair deductions; see to what they mount. — Pope
4.
That which is or may be deducted; the part taken away; abatement; as, a deduction from the yearly rent in compensation for services; deductions from income in calculating income taxes.