calculus

noun

cal·​cu·​lus ˈkal-kyə-ləs 

plural calculi ˈkal-kyə-ˌlī 

-ˌlē

also calculuses

1

a

: a method of computation or calculation in a special notation (as of logic or symbolic logic)

b

: the mathematical methods comprising differential and integral calculus

—often used with the

2

: calculation

… even political conservatives agree that an economic calculus must give way to a strategic consciousness when national or global security is at stake.

—Stephen H. Schneider

3

a

: a concretion usually of mineral salts around organic material found especially in hollow organs or ducts

b

: tartar entry 1 sense 1

4

: a system or arrangement of intricate or interrelated parts

Did you know?

In Latin calculus meant “pebble.” Because the Romans used pebbles to do addition and subtraction on a counting board, the word became associated with computation. Other English derivatives include calculator and calculation. Calculus itself has been borrowed into English as a medical term that refers to masses of matter in the body such as kidney stones (a straightforward extension of the meaning “pebble”) and to refer to a system of mathematical computation.

Synonyms

• math
• calculation
• arithmetic
• mathematics

Examples of calculus in a Sentence

by my calculus the more efficient air conditioner will have paid for itself within a span of five years

Recent Examples on the Web

For banks in the regional tier – who continue to see an upward trend in non-performing loans – the calculus is cold: Scale up aggressively through strategic M&A or prepare to become someone else’s synergy. —Michael Abbott, Forbes.com, 8 July 2025

But that calculus thrusts all sides into a perpetual game of cat-and-mouse, with Iran going to ever-greater lengths to conceal its activities while the U.S. and Israel keep watching for Tehran’s maneuverings. —Nabih Bulos foreign Correspondent, Los Angeles Times, 5 July 2025

There’s an actual path to decisive success, and that can change the political calculus in Washington. —Efrat Lachter, FOXNews.com, 19 June 2025

The goal in using a new extraction approach was to recover as much genetic material as possible, Fu explained, adding that the dense crystalline structure of dental calculus may help prevent the host DNA from being lost. —Katie Hunt, CNN Money, 18 June 2025

Word History

Etymology

borrowed from Latin, "pebble, bladder or kidney stone, pebble used for calculating on a counting board, method or result of calculation, account," perhaps irregular diminutive of calc-, calx "lime, limestone" — more at chalk entry 1

Note: This etymology was accepted by the Latin grammarian Sextus Pompeius Festus, though the senses differ markedly. Perhaps more likely is a connection with Greek káchlēx "shingle (on a shoreline)," usually associated with kachlázein "to splash, murmur, crash (of waves)," taken to be onomatopoeic. However, R. Beekes (Etymological Dictionary of Greek) alludes to the forms kóchlax (in the Septuagint) and áchlax (in the Suda, a tenth-century Byzantine encyclopedia), variants with features (o alternating with a, k alternating with zero) that, according to Beekes, mark borrowing from a non-Indo-European substratum. This might presuppose that both calculus and káchlēx were borrowed from a common source.

First Known Use

1666, in the meaning defined at sense 2

Phrases Containing calculus

• calculus of variations
• differential calculus
• felicific calculus
• functional calculus
• infinitesimal calculus
• integral calculus
• predicate calculus
• propositional calculus
• sentential calculus

Kids Definition

calculus

noun

cal·​cu·​lus ˈkal-kyə-ləs 

plural calculi -ˌlī 

-ˌlē

also calculuses

1

: a branch of higher mathematics concerned especially with rates of change and the finding of lengths, areas, and volumes

2

a

: a mass that consists mostly of mineral salts and is formed in a hollow organ or bodily duct

b

: tartar entry 1 sense 2

Medical Definition

calculus

noun

cal·​cu·​lus -ləs 

plural calculi -ˌlī, -ˌlē  also calculuses

1

: a concretion usually of mineral salts around organic material found especially in hollow organs or ducts

2

: a concretion on teeth : tartar