Butt welding refers to a welding technique where two pieces of metal are joined together by heating their ends until they melt and then pressing them together. However, there are other synonyms for this welding technique that are commonly used in the industry. One such synonym is "strip welding", which refers to a type of butt welding where a strip of metal is used to connect the two pieces of metal. Another synonym is "fusion welding", which implies that the metal is melted and fused together during the welding process. Similarly, "seam welding" refers to a technique where a continuous seam is welded along the length of the joint. Regardless of the terminology, butt welding remains an important technique used in a wide range of industrial applications.