a device for performing mathematical calculations, consisting essentially of a ruler having a sliding piece moving along it, both marked with graduated, usually logarithmic, scales: now largely replaced by the electronic calculator.
Origin of slide rule
1655-1665
1655-65 for earlier sense; 1875-80 for current sense
a mechanical calculating device consisting of two strips, one sliding along a central groove in the other, each strip graduated in two or more logarithmic scales of numbers, trigonometric functions, etc. It employs the same principles as logarithm tables
also slide rule, mathematical calculating tool, 1838, from slide (v.) + rule (n.). So called for its method of operation. Earlier sliding-rule (1660s).