rhumb vs rhumb line

rhumb and rhumb line both are nouns.

Word	Noun	Adjective	Verb	Adverb
rhumb	Yes	No	No	No
rhumb line	Yes	No	No	No

As nouns, rhumb and rhumb line are synonyms defined as:

rhumb and rhumb line: a line on a sphere that cuts all meridians at the same angle; the path taken by a ship or plane that maintains a constant compass direction

Other synonyms of rhumb include loxodrome.

rhumb (noun)	rhumb line (noun)
a line on a sphere that cuts all meridians at the same angle; the path taken by a ship or plane that maintains a constant compass direction	a line on a sphere that cuts all meridians at the same angle; the path taken by a ship or plane that maintains a constant compass direction