Lamberts Chart
 

A straight line on a Lambert Conformal Conic Projection is for the most part a Great Circle.

A Rhumb Line is a line that crosses the meridians at an equal angle.

A meridian is both a rhumb line (constant angle of 0deg with itself) and a great circle - same centre and radius as the earth. That applies regardless of projection.

What changes with the projection is how the meridians appear on a flat piece of paper.

Regards,

DFC

Hope I remember this right from ATPL study.....
On a Lamberts, a great circle is a complex curve concave to the parallel of origin - in practice over short distances it equates to a straight line. Meridians and antimeridians (great circles) are always straight lines, as is a line between 2 points on the parallel of origin (noted on all Lamberts). Simple eh! A Rhumb line is a simple curve concave to the pole of projection, but not considered to be a straight line for charting purposes.
Generally a rhumb line cuts all meridians at the same angle, so at 0deg, a meridian could be described as both a great circle and a rhumb line although I'm not sure that even the CAA word game exams, tried to make this connection. If this were to be the case, wouldnt it be so for all other charts?
Stand to be corrected.....
W