the aggregate of two or more numbers, magnitudes, quantities, or particulars as determined by or as if by the mathematical process of addition: The sum of 6 and 8 is 14.
2.
a particular aggregate or total, esp. with reference to money: The expenses came to an enormous sum.
3.
an indefinite amount or quantity, esp. of money: to lend small sums.
4.
a series of numbers or quantities to be added up.
5.
an arithmetical problem to be solved, or such a problem worked out and having the various steps shown.
6.
the full amount, or the whole.
7.
the substance or gist of a matter, comprehensively or broadly viewed or expressed: the sum of his opinions.
8.
concise or brief form: in sum.
9.
Mathematics.
a.
the limit of the sequence of partial sums of a given infinite series.
to combine into an aggregate or total (often fol. by up).
12.
to ascertain the sum of, as by addition.
13.
to bring into or contain in a small compass (often fol. by up).
–verb (used without object)
14.
to amount (usually fol. by to or into): Their expenses summed into the thousands.
—Verb phrase
15.
sum up,
a.
to reckon: We summed up our assets and liabilities.
b.
to bring into or contain in a brief and comprehensive statement; summarize: to sum up the case for the prosecution.
c.
to form a quick estimate of: I summed him up in a minute.
Origin: 1250–1300; (n.) ME summe < L summa sum, n. use of fem. of summus highest, superl. of superus (see superior); (v.) ME summen (< OF summer) < ML summāre, deriv. of summa
[suhm] 
,noun, verb, summed, sum⋅ming.