Public Peering
Definition: Public Peering is Internet Peering across a shared (more than two party) peering fabric.
Most Internet Exchange Points offer some form of public peering, typically using ethernet as the layer 2 fabric. In some cases, private peering is a reasonable alternative or complementary service.
See the Great Public vs Private Peering Debate for a discussion of why some prefer public peering, but the dominant application is to aggregate lots of peering sessions on a single shared and administered port.