In "De arte navigandi" he announced his discovery and analysis of the curve of double curvature called the rumbus, better known as loxodrome, which is the line traced by a ship cutting the meridians at a constant angle.    From Wordnik.com.  [The Catholic Encyclopedia, Volume 11: New Mexico-Philip] Reference

Mercator also produced the first globe to have rhumb lines (1541), based on his observation that a ship sailing towards the same point of the compass would follow a curve called a loxodrome (also called a rhumb line or spherical helix).    From Wordnik.com.  [Mercator, Gerardus] Reference

His vocabulary alone is worth the cover price - gantries, quinquireme, discalced, carrack, loxodrome, godown, scutch, so shrewd in his deployment of detail, so blessed with good luck and goodwill that we forget the conceit and just enjoy the ride.    From Wordnik.com.  [The Seattle Times] Reference