Introduction, blah blah blah...
also rhumb lines or rumb lines. "This line of constant bearing is called a Rhumb line. The word 'rhumb' (or sometimes rumb and it is the same in French though not very well known) comes from the name of angle measurement representing the 'point' on the old fashioned compass cards. There are 32 'rhumbs' in 360 degrees, hence a rhumb is 11 1/4 degrees." (Source?)