Cross
A cross is a four-way fitting that connects a main run to two opposing outlets at one junction. It has one more opening than a tee, and the generic name does not prove that every outlet is equal; the detailed specification may define a straight or reducing cross. Selection should consider the size and wall at all four ends, each branch direction and load, flow distribution, material, weld access, and piping-stress analysis. The isometric drawing and piping class must define the exact run and outlet arrangement.
Application and duty
Creating a four-way junction where two opposing branches share one location and the exact size arrangement is defined by the design.