Nā'piĕr's-bōnes or Nā'piĕr's-rōds, n. pl.

(nā'peer), n. pl. A set of rods of bone, or other material, each divided into nine spaces, and containing the numbers of a column of the multiplication-table, so that when such of them are placed side by side as have at top the successive numbers of any multiplicand, the product is obtained by adding, in a particular way, the numbers on each of them corresponding to those of the multiplier, found on a rod at the side. It was a contrivance of Baron Napier, the inventor of logarithms, for facilitating the operations of multiplication and division.