rhumb line

American  

noun

1. a curve on the surface of a sphere that cuts all meridians at the same angle. It is the path taken by a vessel or aircraft that maintains a constant compass direction.

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rhumb line British  

noun

1. an imaginary line on the surface of a sphere, such as the earth, that intersects all meridians at the same angle

2. the course navigated by a vessel or aircraft that maintains a uniform compass heading

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Etymology

Origin of rhumb line

First recorded in 1660–70

Example Sentences

See Examples For:

rhumb line

Before the days of GPS, sailors often charted nautical courses using what’s called a rhumb line.

From Slate ● Jan. 21, 2026

The wind held long enough for the boats to slip through, and a half-hour later we were sailing a rhumb line for the beach.

From New York Times ● Dec. 16, 2019

To ensure that every cartouche, sea monster and rhumb line remains vibrant, the men keep the Venetian blinds in their south-facing apartment drawn, as if for a permanent siesta.

From New York Times ● Jan. 23, 2014

The rhumb-line distance to Bermuda is 635 miles, but since no sailing boat can sail the rhumb line exactly, the handicapping distance was 675.

From Time Magazine Archive

Malay began by standing off on the port tack until she was nearly 45 miles west of the rhumb line, a straight-line course to St. David's Head.

From Time Magazine Archive