noun Date: circa 1658 a set of graduated rods (as of wood or bone) invented by John Napier and used for multiplication and division based on the principles of logarithms
NAPIER'S BONES
Meaning of NAPIER'S BONES in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012