Noun
A line which crosses successive meridians at a constant angle; -- called also rhumb line, and loxodromic curve. See Loxodromic.
Source: Webster's dictionaryIf α is neither 0 nor then the above figure of the infinitesimal elements shows that the length of an infinitesimal rhumb line on the sphere between latitudes φ; and φ + δφ is a sec α δφ. Source: Internet
One problem is the variation of scale with latitude, and another is that straight lines on the map ( rhumb lines ), other than the meridians or the equator, do not correspond to great circles. Source: Internet