Calculus

How to spell calculus

8 letters · 3 syllables

How to pronounce calculus

Say the part in capitals loudest.

What does calculus mean?

1. nounThe branch of mathematics dealing with rates of change and the accumulation of quantities, using differentiation and integration.
2. nounA hard stony mass that forms in the body, such as a kidney stone or a deposit of tartar on the teeth.

Calculus in a sentence

• The engineering degree requires two semesters of calculus.

• The scan revealed a small calculus lodged in his left kidney.

• She finally understood limits after struggling with calculus all year.

• The hygienist scraped away the hardened calculus along his gum line.

Where does calculus come from?

Language of origin: Latin

This word comes directly from the Latin calculus, which literally meant 'a small stone' or 'pebble'. It was a diminutive of calx, meaning 'limestone' or 'stone', and the little stones in question were the counters that Romans pushed around on a counting board, an early abacus, to do their sums. Because reckoning was done with these pebbles, the word came to stand for calculation and methodical counting, which is why we still speak of someone's political 'calculus' when we mean their careful reckoning. In the late 1600s the mathematicians Newton and Leibniz attached the term to their new system for studying continuous change, giving us the modern branch of mathematics. The same pebble idea survives in medicine, where a calculus is a hard stone that forms in the body, such as a kidney stone. Knowing that the root is the humble pebble calx helps fix the awkward spelling: there is a single l in the middle and the ending is -ulus, not -ulous.

How the word is built

• calc- (from calx: small stone, pebble)
• -ulus (Latin diminutive suffix)