Abacist

ABACIST

Noun. Late Middle English.

[medieval Latin abacista]

A person who makes calculations with an abacus

As a child, I was a keen reader of Arthur C Clarke, and this word immediately reminds me of his short story Into the Comet. In it, a spaceship's computer malfunctions and is unable to make the calculations necessary for it to return home. Facing certain death, the crew of the ship form a ramshackle production line of abacists, and are able to replicate the calculations of the computer and complete their mission safely.