A joint is made between two metal pieces by closely fitting their surfaces and distributing a molten nonferrous filler metal to the interface by capillary attraction. This process is most accurately termed?

The process described involves closely fitting two metal surfaces and using a molten nonferrous filler metal that flows into the joint by capillary attraction. This characteristic aligns with soldering, which typically involves joining metals at a temperature below the melting point of the base metals. In soldering, a filler material (often a tin-lead alloy or similar nonferrous metal) is melted and drawn into the gap between the pieces, relying on capillary action for effective bonding.

Brazing, while also a process that uses a filler metal, typically occurs at higher temperatures than soldering and can involve nonferrous metals as well but does not specifically emphasize the capillary action in the same way as soldering does. Welding, in contrast, involves melting the base metals themselves to create a joint and does not utilize a separate filler metal in the same manner. Forge welding is a specific type of welding conducted by hammering or applying pressure to solid metal pieces, which doesn't pertain to a filler metal or capillary action.

Thus, the correct terminology for this specific joint-making process is soldering.