Cost sharing is when a portion of project costs are not paid by the sponsor. Cost sharing can take the form of either direct cost sharing or indirect cost sharing. Direct cost sharing involves the transferring of funds from a cost sharing source (department, program, ect.) and placed into the cost sharing fund of the project. Indirect cost sharing is a contribution, by the University, of the Facilities & Administrative costs and is often called waived F&A.
For a more indepth explanation of the different types of cost sharing and how they are used, please refer to the useful links below.