parallel rulers

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plural noun

a pair of straightedges connected by two pivoted crosspieces of equal length so as to be parallel at all times, used for various navigational purposes, especially for transferring the bearing of a plotted course to a compass rose.

Origin of parallel rulers

First recorded in 1695–1705
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for parallel rulers

Historical Examples of parallel rulers

  • Hence we find him first making brass scales, parallel-rulers and quadrants.

    James Watt

    Andrew Carnegie