sum

Syllabification: (sum)

Pronunciation: /səm/

Definition of sum

2 (the sum of) the total amount resulting from the addition of two or more numbers, amounts, or items:the sum of two prime numbers
the total amount of something that exists:the sum of his own knowledge

[with object] technical

find the sum of (two or more amounts):if we sum these equations we obtain x
[no object] (sum to) (of two or more amounts) add up to a specified total:these additional probabilities must sum to 1

Phrases

in sum: to sum up; in summary:this interpretation does little, in sum, to add to our understanding

sum up: give a brief summary of something:Gerard will open the debate and I will sum up; Law (of a judge) review the evidence at the end of a case, and direct the jury regarding points of law.
sum someone/something up: express a concise idea of the nature or character of a person or thing:selfish—that summed her up

Middle English: via Old French from Latin summa 'main part, sum total', feminine of summus 'highest'

Definition of sum in the British & World English dictionary