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?

Solving calculus equations on a chalkboard allows one to erase mistakes, and also hints at the word’s rocky, and possibly chalky, past. Calculus entered English in the 17th century from Latin, in which it referred to a pebble, often one used specifically for adding and subtracting on a counting board. The word thus became associated with computation; the phrase ponere calculos, literally, “to place pebbles,” meant “to carry out a computation.” The Latin calculus, in turn, is thought to perhaps come from the noun calx, meaning “lime” or “limestone,” which is also the ancestor of the English word chalk. Today, in addition to referring to an advanced branch of mathematics, calculus can also be used generally for the act of solving or figuring something out, and as a medical term for the tartar that forms on teeth, among other things. Whichever way it’s used, we think that calculus rocks.

Synonyms of calculus

• 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

The premise forces viewers into a slippery moral calculus from the opening episode, one that grows increasingly grotesque with each turn. —Virgie Tovar, Forbes.com, 23 Jan. 2026

The more the fines build up, the more likely the calculus will shift for your building to take the compost mandate seriously. —Clio Chang, Curbed, 21 Jan. 2026

And what of the emerging calculus, whispered but increasingly believed, that being an American ally is becoming more dangerous than being America’s enemy? —Ivan Krastev, Time, 21 Jan. 2026

That calculus has shifted, and social media deserves most of the credit. —Matthew Kayser, Ascend Agency, 16 Jan. 2026

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

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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