Multiple stud arrangements at an exterior corner
A multiple-stud post made up of at least three studs, or the equivalent, is generally used at exterior corners and intersections to provide a good tie between adjoining walls and nailing support for the interior finish and exterior sheathing (Figures 69 and 70). Corners and intersections, however, must be framed with at least two studs.
Source : Canada Mortgage and Housing Corporation (CMHC)
A stud is a vertical framing member which forms part of a wall or partition. Also known as wall studs, they are a fundamental component of frame construction and are typically made of timber. However, steel studs are increasingly popular, particularly for non load-bearing walls and firewalls.