Punching shear is called 2-way shear partly because it is generally associated with point supports in 2-way slabs, and partly to differentiate it from one way shear in that punching shear applies around a point support and one way shear applies along a line. Punching shear can apply in a slab that is reinforced and bent in one direction if a point load is applied in a concentrated location so it is not strictly a phenomenon of 2-way slabs.
Then what is the difference between one way and two way shear? I know that the distance of d from coloum face for one way shear...here I asked you the difference in real life structure?
One way shear would normally be associated with a slab that is reinforced on one direction and spanning only in that direction. One way shear applies along a line such as when the end of a slab is supported along its width by a beam or wall. Two way shear typically applies around a point support and not along a line support.