Refinancing is financing of one loan by another. Or in other words, one loan is replaced by another.
Refinancing institutions are important institutions who give loans to other institutions who ultimately gives loans to the end customers. For example, the National Housing Bank is a refinancing institution in the field of housing finance in India. It doesn’t give any direct loans to the house loan applicants. Rather, it refinances (give loans) to those institutions (eg. Commercial banks) who gives home loans. Similarly, NABARD is another refinancing institution, but in the field of agricultural credit.