Definition of "Sum" :
noun: the whole amount
noun: a quantity obtained by the addition of a group of numbers
noun: the choicest or most essential or most vital part of some idea or experience
noun: the final aggregate
"The sum of all our troubles did not equal the misery they suffered."
noun: a set containing all and only the members of two or more given sets
noun: a quantity of money
"He borrowed a large sum."
verb: determine the sum of
verb: be a summary of
"The abstract summarizes the main ideas in the paper."