During this discussion there was some debate as to the definition of the term "Prefabrication" and "Modularization".
MacGraw Hill have an excellent definition of these terms and more in their Prefabrication and Modularization Smart Market Report.
The manufacture and remote assembly of major interior or exterior sections of a building (e.g., wall, floor, roof) of one or multiple material types which may include portions of a system (e.g., electrical, plumbing). Examples include curtain wall, structural insulated panels and entire building modules.
Manufacturing processes generally taking place at a specialized facility, in which various materials are joined to form a component part of a final installation. Examples include trusses, joists, structural steel and precast concrete. Model-driven prefabrication describes the use of the BIM model to enable prefabrication and assembly of building components both off and on the construction site.
The fabrication or assembly of components (no manufacturing processes) off-site or on the construction site but at a location other than the point of installation. The process is usually completed by specialty contractors (e.g., finish carpentry).
Permanent Modular Construction (PMC):
A design and construction process performed in a manufacturing facility, which produces building components or modules that are constructed to be transported to a permanent building site.