Melt down is a term used to describe the process of melting a solid material, such as metal, into a liquid form. The two crossword solutions for this term are RENDER (6 letters) and THAW (4 letters). RENDER is a verb meaning to melt down fat or other substances in order to separate them from the rest of the material. THAW is a verb meaning to cause something that was frozen to become liquid. Both of these words can be used to describe the process of melting down a solid material.