Webster’s Revised Unabridged Dictionary · 1913
Napier's bones
Na′pi·er's bones′, Na′pi·er's rods′ . A set of rods, made of bone or other material, each divided into nine spaces, and containing the numbers of a column of the multiplication table; — a contrivance of Baron Napier, the inventor of logarithms, for facilitating the operations of multiplication and division.