parallel rulers
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
Words nearby parallel rulers
British Dictionary definitions for parallel ruler
parallel ruler
noun
engineering
a drawing instrument in which two parallel edges are connected so that they remain parallel, although the distance between them can be varied