Deduct means to take away a portion of something, to subtract something. Deduct is a transitive verb, which is a verb that takes an object. Related words are deducts, deducted, deducting and the noun form, deduction, which causes the confusion between deduct and deduce. Deduct comes from the Latin word deducere, which means lead down, bring away.
Deduce means to draw a conclusion through the use of logic and reason. Deduce is a transitive verb, related words are deduces, deduced, deducing, deductive, deductively and the noun form, deduction. Interestingly, deduce is also derived from the Latin word deducere, and several hundred years ago, the words deduct and deduce were interchangeable. Today, the definitions of deduct and deduce have diverged. While the noun form is identical for each word, the meaning differs according to context.
Examples
To deduce literacy rates, the research team used a method that Barak Sober, from the Department of Applied Mathematics at Tel Aviv University, compared to forensic handwriting analysis adapted to ancient times. (The New York Times)
And they deduce from this the need for an immediate expansionary boost to macroeconomic policies. (The Wall Street Journal)
Almost all judgments rely upon inductive reasoning, and that inevitably involves a greater or lesser degree of uncertainty (e.g., “Every time I’ve thrown a curveball, he’s swung and missed; therefore, if I do it now, he’ll probably swing and miss again”), rather than upon the more rigorous process of logical deduction from indisputable premises to indubitable conclusions (e.g., “All men are mortal. Socrates is a man. Therefore, Socrates is mortal”) (The Deseret News)
The current MTS Compass Card system only sells passes to customers — not allowing “stored value,” as it’s known in the industry, so riders can deduct one trip at a time from a card balance. (The San Diego Union-Tribune)
The central board has modified its bylaws and with the approval of its governing body declared that it will deduct 50% of the application fee as processing charges, as compared to the 10% being done earlier. (The Times of India)
A Nets spokesman told The Straits Times: “Cases of a second deduction are uncommon but may arise if the operator’s system did not record the first deduction successfully and may proceed to initiate another deduction. (The Straits Times)