a device consisting of an arrangement of cords variously colored and knotted, used by the ancient Peruvians to keep accounts, record events, etc.
See quipu in American Heritage Dictionary 4
(kēˈpo͞o)
noun
A record-keeping device of the Inca empire consisting of a series of variously colored strings attached to a base rope and knotted so as to encode information, used especially for accounting purposes.