noun

1. That which is deducted; that which is subtracted or removed

2. A sum that can be removed from tax calculations; something that is written off

   “You might want to donate the old junk and just take the deduction.”

3. A 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.

Synonyms: extract, reduction