Hello Ananth
Pseudowire in general is a feature that allows you to create a Layer 2 connection between two remote devices, over a Layer 3 infrastructure. An example of where pseudowire is applied is in the L2TPv3 protocol. More about L2TPv3 can be found at this lesson:
Within the context of MPLS however, pseudowire is used to provide end-to-end services across an MPLS network. More about what these are and how they can be implemented can be found here:
I hope this has been helpful!
Laz