A projection in which latitude lines are parallel but meridians are curves.
See also Cylindrical Projection, Eckert IV Projection, Eckert VI Projection, Mollweide Projection, Robinson Projection, Sinusoidal Projection
References
Dana, P. H. ``Map Projections.''
http://www.utexas.edu/depts/grg/gcraft/notes/mapproj/mapproj.html.