Other forms: calculi
Calculus is the mathematics of change and of areas under curves. Do calculus, differential calculus, integral calculus.
It divides into differential calculus, which handles rates of change, and integral calculus, which handles accumulation — and the fundamental theorem says the two are inverse operations, which is one of the great results in mathematics. Newton and Leibniz developed it independently and argued about it for decades. Note that a calculus is also a stone in the body, and that the word means a pebble.
1nouncalculusThe mathematics of change and of areas under curves.
“Engineers use calculus to work out how bridges will bend under heavy loads.”
2nounstoneA stone formed in the body.
“The surgeon removed a small calculus from the patient's kidney.”
calculus is a branch of mathematics, or a stone.
Latin calculus is a little stone, a diminutive of calx, limestone. Pebbles were used as counters on an abacus, so calculate and calculus come from stones.
Built from
Borrowed from Latin calculus (“a pebble or stone used as reckoning counters in abacus”), diminutive of calx (“limestone”) + -ulus*.
Etymology from Wiktionary, CC BY-SA