rhumb line

 

 rhumb line on Wikipedia

rhumb line (plural rhumb lines)

1. (nautical) A line that cuts all meridians at the same angle, the path of a vessel that maintains a constant compass direction.

   Synonyms: rhumb, loxodrome

   Coordinate term: orthodrome

   • 1964, David Greenhood, Mapping, University of Chicago Press, →ISBN, page 128:

     On portolan maps rhumb lines were all the go long before Mercator's time. […] It's a different matter putting a straight rhumb line on a map made for a round world. And on a map made for the whole world.