Pluripotency - when a cell can specialise into most cell types (in mammals, this typically means all body cell types other than the placenta).
Multipotency - when a cell can differentiate into a few different cell types, but not all cell types (for example haematopoetic stem cells which can become erythrocytes, macrophages, neutrophils, T and B lymphocytes, etc., but cannot become nerve cells).
Regenerative medicine is the branch of medicine concerned with replacement of damaged tissues. Transplantation of allogenic tissue (from other organisms) brings with it risks of rejection by the immune system, so research in this area is often focused on the use of autogenic tissue (from the 'self'). This tissue can be grown from stem cells.