noun
: a projection (as of a sphere or a spheroid) on the surface of a cylinder ; specifically : any of numerous map projections of the terrestrial sphere on the surface of a cylinder that is then unrolled as a plane, the parallels and meridians appearing as straight lines perpendicular to each other if the cylinder is tangent over the sphere at the equator and all parallels as well as the points of the poles if shown appearing as the same length as the equator