[1] : The Collaborative International Dictionary of English v.0.48

sum \sum\, v. t. imp.  p. p. summed; p. pr.  vb. n.
   summing. cf. f. sommer, ll. summare.
   1. to bring together into one whole; to collect into one
      amount; to cast up, as a column of figures; to ascertain
      the totality of; -- usually with up.
      1913 webster

            the mind doth value every moment, and then the hour
            doth rather sum up the moments, than divide the day.
                                                  --bacon.
      1913 webster

   2. to bring or collect into a small compass; to comprise in a
      few words; to condense; -- usually with up.
      1913 webster

            "go to the ant, thou sluggard," in few words sums up
            the moral of this fable.              --l'estrange.
      1913 webster

            he sums their virtues in himself alone. --dryden.
      1913 webster

   3. falconry to have the feathers full grown; to furnish
      with complete, or full-grown, plumage.
      1913 webster

            but feathered soon and fledge
            they summed their pens wings.       --milton.
      1913 webster

   summing up, a compendium or abridgment; a recapitulation; a
      r'esum'e; a summary.
      1913 webster

   syn: to cast up; collect; comprise; condense; comprehend;
        compute.
        1913 webster sumac
see also:
summed summing summing up 

[2] : WordNet (r) 2.0

sum
     n 1: a quantity of money; "he borrowed a large sum"; "the amount
          he had in cash was insufficient" syn: sum of money, amount,
           amount of money
     2: a quantity obtained by addition syn: amount, total
     3: the final aggregate; "the sum of all our troubles did not
        equal the misery they suffered" syn: summation, sum
        total
     4: the choicest or most essential or most vital part of some
        idea or experience; "the gist of the prosecutor's
        argument"; "the heart and soul of the republican party";
        "the nub of the story" syn: kernel, substance, core,
         center, essence, gist, heart, heart and soul, inwardness,
         marrow, meat, nub, pith, nitty-gritty
     5: the whole amount syn: total, totality, aggregate
     6: the basic unit of money in uzbekistan
     7: 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" syn:
         union, join
     v 1: be a summary of; "the abstract summarizes the main ideas in
          the paper" syn: summarize, summarise, sum up
     2: determine the sum of; "add all the people in this town to
        those of the neighboring town" syn: total, tot, tot
        up, sum up, summate, tote up, add, add together,
         tally, add up
     also: summing, summed
see also:
sum of money amount amount of money total summation sum total 
kernel substance core center essence 
gist heart heart and soul inwardness marrow 
meat nub pith nitty-gritty totality 
aggregate union join summarize summarise 
sum up tot tot up summate tote up 
add add together tally add up summing 
summed 

[3] : WordNet (r) 2.0

summing
     see sum
see also:
sum 

Summing >> S Words
Summing, definition of term: Summing
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