Definition of sum noun from the Oxford Advanced American Dictionary

        

    sum

     noun
    noun
    NAmE//sʌm//
     
     
    jump to other results
  1. 1 [countable] sum (of something) an amount of money You will be fined the sum of $200. a large sum of money a six-figure sum Huge sums have been invested in this project. see also lump sum
  2. 2[countable, usually singular] sum (of something) the number you get when you add two or more numbers together The sum of 7 and 12 is 19.
  3. 3(also sum total) [singular] the sum of something all of something, especially when you think that it is not very much This is the sum of my achievements so far.
  4. 4 [countable] a simple problem that involves calculating numbers If I have my sums right, I should be able to afford the rent.
  5. Idioms
    be greater/more than the sum of its parts
     
    jump to other results
    to be better or more effective as a group than you would think just by looking at the individual members of the group
    in sum(formal)
     
    jump to other results
    used to introduce a short statement of the main points of a discussion, speech, etc. In sum, we have no chance of winning the case.
See the Oxford Advanced Learner's Dictionary entry: sum