Editing Rhumb line (section)

==Etymology and historical description==
The word ''loxodrome'' comes from [[Ancient Greek language|Ancient Greek]] λοξός ''loxós'': "oblique" + δρόμος ''drómos'': "running" (from δραμεῖν ''drameîn'': "to run"). The word ''rhumb'' may come from [[Spanish language|Spanish]] or [[Portuguese language|Portuguese]] ''rumbo/rumo'' ("course" or "direction") and Greek [[rhombus|ῥόμβος]] ''rhómbos'',<ref>''[http://www.thefreedictionary.com/rhumb Rhumb]'' at TheFreeDictionary</ref> from ''rhémbein''.

The 1878 edition of ''The Globe Encyclopaedia of Universal Information'' describes a ''loxodrome line'' as:<ref name="Globe"/>

<blockquote>'''Loxodrom′ic''' Line is a curve which cuts every member of a system of lines of curvature of a given surface at the same angle. A ship sailing towards the same point of the compass describes such a line which cuts all the meridians at the same angle. In Mercator's Projection (q.v.) the Loxodromic lines are evidently straight.<ref name="Globe">Ross, J.M. (editor) (1878). ''[https://archive.org/details/globeencyclopae01rossgoog The Globe Encyclopaedia of Universal Information]'', Vol. IV, Edinburgh-Scotland, Thomas C. Jack, Grange Publishing Works, retrieved from [[Google Books]] 2009-03-18;</ref></blockquote>

A misunderstanding could arise because the term "rhumb" had no precise meaning when it came into use. It applied equally well to the [[windrose line]]s as it did to loxodromes because the term only applied "locally" and only meant whatever a sailor did in order to sail with constant [[bearing (navigation)|bearing]], with all the imprecision that that implies. Therefore, "rhumb" was applicable to the straight lines on [[portolan]]s when portolans were in use, as well as always applicable to straight lines on Mercator charts. For short distances portolan "rhumbs" do not meaningfully differ from Mercator rhumbs, but these days "rhumb" is synonymous with the mathematically precise "loxodrome" because it has been made synonymous retrospectively.
As Leo Bagrow states:<ref name="Bagrow2010">{{cite book|author=Leo Bagrow|title=History of Cartography|url=https://books.google.com/books?id=OBeB4tDmJv8C&pg=PA65|year=2010|publisher=Transaction Publishers|isbn=978-1-4128-2518-4|page=65}}</ref>
<blockquote>the word ('Rhumbline') is wrongly applied to the sea-charts of this period, since a loxodrome gives an accurate course only when the chart is drawn on a suitable projection. Cartometric investigation has revealed that no projection was used in the early charts, for which we therefore retain the name 'portolan'.</blockquote>