sum

¹ American  

[suhm] / sʌm /

noun

1. 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, especially with reference to money.

   The expenses came to an enormous sum.

3. an indefinite amount or quantity, especially 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.

   1. the limit of the sequence of partial sums of a given infinite series.

   2. union.

10. a summary.

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verb (used with object)

summed, summing

1. to combine into an aggregate or total (often followed byup ).

2. to ascertain the sum of, as by addition.

3. to bring into or contain in a small compass (often followed byup ).

verb (used without object)

summed, summing

1. to amount (usually followed by to orinto ).

   Their expenses summed into the thousands.

verb phrase

1. sum up

   1. to reckon.

      We summed up our assets and liabilities.

   2. to bring into or contain in a brief and comprehensive statement; summarize.

      to sum up the case for the prosecution.

   3. to form a quick estimate of.

      I summed him up in a minute.

SUM ² American  

1. surface-to-underwater missile.

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sum- ³ American  

1. variant of sub- before m: summon.

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sum ¹ British  

/ sʌm /

noun

1. 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

2. one or more columns or rows of numbers to be added, subtracted, multiplied, or divided

3. maths the limit of a series of sums of the first n terms of a converging infinite series as n tends to infinity

4. (plural) another name for number work

5. a quantity, esp of money

   he borrows enormous sums

6. the essence or gist of a matter (esp in the phrases in sum, in sum and substance )

7. a less common word for summary

8. archaic the summit or maximum

9. (modifier) complete or final (esp in the phrase sum total )

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verb

1. (often foll by up) to add or form a total of (something)

2. (tr) to calculate the sum of (the terms in a sequence)

sum ² British  

/ sʊm /

noun

1. the standard monetary unit of Uzbekistan, divided into 100 tiyin

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sum Scientific  

/ sŭm /

1. The result of adding numbers or quantities. The sum of 6 and 9, for example, is 15, and the sum of 4 x and 5 x is 9 x.

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Related Words

See number.

Other Word Forms

• outsum verb (used with object)
• sumless adjective
• sumlessness noun

Etymology

Origin of sum

First recorded in 1250–1300; (noun) Middle English summe, from Latin summa “sum,” noun use of feminine of summus “highest,” superlative of superus ( see superior); (verb) Middle English summen (from Old French summer ), from Medieval Latin summāre, derivative of summa

Explanation

When you determine the sum, you add up all the numbers. When you sum something up, you focus on all of its important points. The word sum can also refer to a certain amount of money. A new car might cost you a huge sum of money. But if you sum or add up all its benefits, you might be able to justify spending so much. You calculate the total on a restaurant bill when you sum up the prices of everything you ordered. Sum doesn't have to refer strictly to numbers. When you sum something up, you're giving an overview or general statement about it.

Example Sentences

The system will process refunds for importers as one lump sum, rather than making businesses apply item by item.

From BBC • Apr. 20, 2026

That’s a modest sum, but that’s what it would take to give yourself a reasonable chance of the money lasting the next 30 years.

From MarketWatch • Apr. 19, 2026

That sum is roughly equal to Iran’s oil revenue frozen in Qatar, plus what Iran is owed by Iraq for electricity.

From The Wall Street Journal • Apr. 17, 2026

Annual totals may sum to greater than 100% because of rounding.

From The Wall Street Journal • Apr. 15, 2026

A painting worth a sum too staggering to estimate.

From "The Mona Lisa Vanishes" by Nicholas Day

Related Words

• amount
• bulk
• quantity
• value
• worth