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calculus

n.
US //ˈkæɫkjəɫəs// UK //kˈælkjʊləs// cal·cu·lus
  1. 1 advanced mathematics (n.)
    B2 Upper Intermediate Math

    a branch of advanced mathematics that deals with how things change, such as the speed of a moving object.

    the branch of mathematics that deals with the finding and properties of derivatives and integrals of functions. Uncountable in this sense.

    Example

    She had to study calculus in her first year of engineering at university.

    Example

    The physics professor explained how integral calculus could be used to determine the exact volume of an irregular solid.

    Usage

    Usually used without an article when referring to the field of study.
  2. 2 dental plaque (n.)
    C1 Advanced Technical Medicine

    hard, yellowish substance that forms on teeth when they are not cleaned properly.

    a hard yellowish deposit on the teeth, consisting of calcium phosphate and organic matter. Uncountable in this dental context.

    Example

    Regular brushing helps prevent the buildup of calculus on your teeth.

    Example

    The dental hygienist used a specialized tool to remove the stubborn calculus that had accumulated below the gum line.

    Teacher's tip

    In everyday conversation, most people use the word 'tartar' instead of 'calculus'.
    • tartar
  3. 3 a body stone (n.)
    C2 Proficiency Technical Medicine

    a small, hard stone that forms inside an organ like the kidney.

    a concretion of minerals formed within the body, especially in the kidney or gallbladder. Countable in this medical sense.

    Example

    The doctor found a small calculus in the patient's gallbladder.

    Example

    The surgeon successfully removed a renal calculus that had been causing the patient significant discomfort for several months.
  4. 4 a way of deciding (n.)
    C1 Advanced Academic Formal

    a way of calculating or thinking about a situation to make a decision.

    a particular method or system of calculation or reasoning, often applied to political or social strategy.

    Example

    The political calculus changed after the new law was passed.

    Example

    The CEO's strategic calculus involved weighing the potential for rapid growth against the significant risks of entering an unstable market.
Origin

* Borrowed from Latin calculus (“a pebble or stone used as reckoning counters in abacus”), diminutive of calx (“limestone”) + -ulus. * Mathematical topic is from differential calculus.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Related words

Last updated June 20, 2026