counter

Latin 'computare' meant to reckon or settle accounts, built from 'com-' (together) and 'putare' (to reckon, to prune). By the medieval period, 'computatorium' named the flat surface where calculations were performed: a table covered with a grid of lines or cloth squares across which merchants moved tokens to calculate sums. The physical object and the action it supported shared a root.

Old French shortened 'computatorium' to 'conteor' and later 'comptoir,' and the counting table became essential commercial furniture from the 12th century onward. In a merchant's hall or a money-changer's stall, the counter was where transactions were settled, disputes resolved, and accounts closed. The surface itself was the proof of the transaction.

English borrowed 'counter' from Old French in the 14th century, initially for the counting table specifically. By 1400, the word also named the small tokens used to perform arithmetic on the table's grid — a counter was both the surface and the disc you slid across it. The Exchequer of England used a checkerboard-patterned counting cloth, which gave its name to the royal treasury.

The 17th century extended 'counter' to any horizontal surface used for display or service: in a shop, a bar, a kitchen. The arithmetic meaning faded as the surface meaning expanded. Today almost no one standing at a kitchen counter thinks of medieval arithmetic, but the Roman accountant is still inside the word.