|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|
|the offspring of a zebra and a donkey.|
|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
a device consisting of graduated scales capable of relative movement, by means of which simple calculations may be carried out mechanically. Typical slide rules contain scales for multiplying, dividing, and extracting square roots, and some also contain scales for calculating trigonometric functions and logarithms. The slide rule remained an essential tool in science and engineering and was widely used in business and industry until it was superseded by the portable electronic calculator late in the 20th century.
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