sum sum /ˈsʌm/

noun

1. () A quantity of money  ( amount of money , sum of money , sum , amount )
   a quantity of money
    He borrowed a large sum
   he borrowed a large sum
    The amount he had in cash was insufficient
   the amount he had in cash was insufficient
   
2. () A quantity obtained by the addition of a group of numbers  ( sum , amount , total )
   a quantity obtained by the addition of a group of numbers
   
3. () The whole amount  ( totality , aggregate , sum , total )
   the whole amount
     The cashier calculated the total amount of the purchase.
   The cashier calculated the total amount of the purchase.
   
4. () The choicest or most essential or most vital part of some idea or experience  ( centre [Canadian, British] , gist , heart and soul , inwardness , kernel , marrow , meat , nitty-gritty , nub , center [American] , core , essence , heart , pith , substance , sum )
   the choicest or most essential or most vital part of some idea or experience
    The gist of the prosecutor's argument
   the gist of the prosecutor's argument
    The heart and soul of the Republican Party
   the heart and soul of the Republican Party
    The nub of the story
   the nub of the story
   
5. () The final aggregate  ( sum total , summation , sum )
   the final aggregate
    The sum of all our troubles did not equal the misery they suffered
   the sum of all our troubles did not equal the misery they suffered
   
6. A set containing all and only the members of two or more given sets  ( join , sum , union )
   a set containing all and only the members of two or more given sets
    Let C be the union of the sets A and B
   let C be the union of the sets A and B
   

verb

1. Determine the sum of  ( add together , sum , sum up , add , summate , tally , tot , tot up , tote up , add up , total )
   determine the sum of
    Add all the people in this town to those of the neighboring town
   Add all the people in this town to those of the neighboring town
   
2. Be a summary of  ( sum , sum up , summarise [British] , summarize )
   be a summary of
    The abstract summarizes the main ideas in the paper
   The abstract summarizes the main ideas in the paper