Origin of sum

1250–1300; (noun) Middle English summe < Latin summa sum, noun use of feminine of summus highest, superlative of superus (see superior); (v.) Middle English summen (< Old French summer) < Medieval Latin summāre, derivative of summa
Related formssum·less, adjectivesum·less·ness, nounout·sum, verb (used with object), out·summed, out·sum·ming.
Can be confusedsome sum (see usage note at some)

Synonyms for sum

1. See number.


surface-to-underwater missile.


variant of sub- before m: summon.

cogito, ergo sum

[koh-gi-toh er-goh soo m; English koj-i-toh ur-goh suhm, er-goh]


I think, therefore I am (stated by Descartes as the first principle in resolving universal doubt).
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for sum

Contemporary Examples of sum

Historical Examples of sum

  • This sum of money and the knowledge of the printer's trade made up his capital.

  • The word thinking, defined early in this chapter, is broadly used to denote the sum of all the intellectual faculties.

  • This, he believed, was the sum of good government; and this was the government which he was determined to establish.

  • He had originally possessed but twenty thousand francs, a sum which in no wise corresponded with his lofty pretensions.

    The Count's Millions

    Emile Gaboriau

  • How to dispose of this sum for the best advantage of his family, was matter of anxious consideration to Butler.

British Dictionary definitions for sum




  1. the result of the addition of numbers, quantities, objects, etc
  2. the cardinality of the union of disjoint sets whose cardinalities are the given numbers
one or more columns or rows of numbers to be added, subtracted, multiplied, or divided
maths the limit of a series of sums of the first n terms of a converging infinite series as n tends to infinity
(plural) another name for number work
a quantity, esp of moneyhe borrows enormous sums
the essence or gist of a matter (esp in the phrases in sum, in sum and substance)
a less common word for summary
archaic the summit or maximum
(modifier) complete or final (esp in the phrase sum total)

verb sums, summing or summed

(often foll by up) to add or form a total of (something)
(tr) to calculate the sum of (the terms in a sequence)
See also sum up

Word Origin for sum

C13 summe, from Old French, from Latin summa the top, sum, from summus highest, from superus in a higher position; see super



noun plural sumy (sʊmɪ)

the standard monetary unit of Uzbekistan, divided into 100 tiyin

cogito, ergo sum

I think, therefore I am; the basis of Descartes' philosophy
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for sum

late 13c., "quantity or amount of money," from Anglo-French and Old French summe (13c.), from Latin summa "total number, whole, essence, gist," noun use of fem. of summus "highest," from PIE *sup-mos-, from root *uper "over" (see super-).

The sense development from "highest" to "total number" is probably via the Roman custom of adding up a stack of figures from the bottom and writing the sum at the top, rather than at the bottom as we do now (cf. the bottom line). Meaning "total number of anything" is recorded from late 14c. Meaning "essence of a writing or speech" also is attested from late 14c. The verb is attested from c.1300; meaning "briefly state the substance of" (now usually with up) is first recorded 1620s. Sum-total is attested from late 14c., from Medieval Latin summa totalis.

Online Etymology Dictionary, © 2010 Douglas Harper

Science definitions for sum



The result of adding numbers or quantities. The sum of 6 and 9, for example, is 15, and the sum of 4x and 5x is 9x.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.