Late 17th century; earliest use found in Edward Phillips (b. 1630), writer and biographer. From the genitive of the name of John Napier + the plural of rod.
Definition of Napier's rods in US English:
Napier's rods
nounˌneɪpɪəz ˈrɒdz
Mathematics
Napier's bones.
Origin
Late 17th century; earliest use found in Edward Phillips (b. 1630), writer and biographer. From the genitive of the name of John Napier + the plural of rod.