n. & v.
n. 1 the total amount resulting from the addition of two or more items, facts, ideas, feelings, etc. (the sum of two and three is five; the sum of their objections is this). 2 a particular amount of money (paid a large sum for it). 3 a an arithmetical problem (could not work out the sum). b (esp. pl.) colloq. arithmetic work, esp. at an elementary level (was good at sums).
v.tr. (summed, summing) find the sum of. in sum in brief. summing-up 1 a review of evidence and a direction given by a judge to a jury. 2 a recapitulation of the main points of an argument, case, etc. sum total = sense 1 of n. sum up 1 (esp. of a judge) recapitulate or review the evidence in a case etc. 2 form or express an idea of the character of (a person, situation, etc.). 3 collect into or express as a total or whole.
[ ME f. OF summe, somme f. L summa main part, fem. of summus highest ]