Noun
A joint in which the edges or ends of the pieces united come squarely together instead of overlapping. See 1st Butt, 8.
Source: Webster's dictionaryGeometry main Common welding joint types – (1) Square butt joint, (2) V butt joint, (3) Lap joint, (4) T-joint Welds can be geometrically prepared in many different ways. Source: Internet