A single-sided tangential cutting insert has a peripheral side surface with N identical major sides. The cutting insert has 360°/N rotational symmetry about an insert axis passing through top and bottom surfaces of the insert, where N is an integer greater than 2 and each major side is located between and merges with an adjacent major side. A cutting edge is formed at the intersection of a relief surface and a rake surface. The rake surface is located in the peripheral side surface and extends in an inward direction of the cutting insert from its associated cutting edge to a side surface of the associated major side. At least a portion of the relief surface is located in the top surface.