study of sailing along rhumb-lines
• (n.) The science of loxodromics.
Lox·od'ro·my noun [ Confer French loxodromic .] The science of loxodromics. [ R.]
loxodromy 1. The art of oblique sailing. 2. The study of sailing along rhumb-lines (course along the surface of a sphere crossing successive meridians at the same angle).