Use this tag when the question deals with the design of welds or their uses. For questions about the physical process of making welds, use the [welding] tag.
Welding is the process of combining two pieces (typically metals) together. To successfully create welds, an experienced welder (person) with the proper tools can be required. Welding is a specialized profession much like carpentry or plumbing.
Not all welds require the same level of care and expertise.