An arc-welding process wherein coalescence is produced by heating with an arc drawn between a metal stud or similar part, and the other work part, until the surfaces to be joined are properly heated, when they are brought together under pressure. Shielding is obtained from an inert gas such as helium or argon.

An arc-welding process wherein the coalescence is produced by heating with an arc between single tungsten (non-consumable) electrode and the work. Shielding is obtained from a gas or gas mixture. Pressure may or may not be used and filler metal may or may not be used. (This process has sometimes been called TIG welding.)

A group of welding processes wherein coalescence is produced by heating with a gas flame or flames, with or without the application of pressure, and with or without the use of filler metal.

The total included angle of the groove between parts to be joined by a groove weld.