Definition of sum:

part of speech: verb

To collect or add into one whole, as particulars or several numbers; to bring into a small compass; to compute; to condense.

part of speech: noun

That which two or more numbers, quantities, or particulars form when added or placed together; the amount or whole of anything; the total; a quantity of money; the substance; an abridgment; height.

Usage examples:

• I believe I ought to have offered a definite sum ' she went on, half to herself. Susan Warner in "The Gold of Chickaree".

• Now as to the reward, what sum would you think sufficient? Leonard Merrick in "A Chair on The Boulevard".

• " The Lord only knows where I am to pick up that sum Emma D. E. N. Southworth in "Her Mother's Secret".