The term 'Early Calculator' can be summarized as an ABACUS, which is a 6-letter word. An ABACUS is an ancient calculating tool that was used in many parts of the world for centuries. It consists of a frame with beads or disks that are moved along rods to perform calculations. Abacuses were used for basic arithmetic operations such as addition, subtraction, multiplication, and division. They were also used to solve more complex problems such as fractions and square roots. Abacuses are still used today in some parts of the world, although they have been largely replaced by modern calculators.