calculus

Where does the word "calculus" come from? It comes from Latin calculus, passing through Modern Latin before entering English (1660s).

Calculus’s story begins in Latin: calculus meant “pebble.” A small pebble, from 'calx', limestone; Romans counted with pebbles on a board. By 1680s, the word had taken hold in Modern Latin as calculus. Gottfried Wilhelm Leibniz published his 'calculus differentialis', a method of calculation, in 1684. It reached English by 1660s as calculus. Doctors kept the old sense for kidney and bladder stones. Today, calculus means a branch of mathematics dealing with rates of change; a hard stone in the body.

1. Stage 1 · Latin · ancient calculus "pebble", a small pebble, from 'calx', limestone; Romans counted with pebbles on a board.
2. Stage 2 · Modern Latin · 1680s calculus "method of calculation", Gottfried Wilhelm Leibniz published his 'calculus differentialis', a method of calculation, in 1684.
3. Stage 3 · English · 1660s calculus "calculus; body stone", doctors kept the old sense for kidney and bladder stones.