(1):

(n.) That which is deduced or drawn from premises by a process of reasoning; an inference; a conclusion.

(2):

(n.) Act or process of deducing or inferring.

(3):

(n.) Act of deducting or taking away; subtraction; as, the deduction of the subtrahend from the minuend.

(4):

(n.) That which is deducted; the part taken away; abatement; as, a deduction from the yearly rent.