The term 'join with a metal fastener' can be answered with the word 'RIVET, ' which is a five-letter word. A RIVET is a mechanical fastener that is used to join two or more pieces of material together. It is usually made of metal and has a cylindrical shape with a head on one end. The other end is inserted into a hole in the materials being joined and then the head is hammered or pressed down to secure the joint. Rivets are commonly used in construction, manufacturing, and engineering applications.