What is the difference between a prefabricated building and pre engineered building?

The pre Engineered building or conventional building  method of building a house or any building  is to transport bricks, timber, cement, sand, and construction aggregate, etc to the site, and to construct the any building on site from these materials. In prefabricated construction, only the foundations and floor slabs are constructed in this way, while sections of walls and roof are prefabricated in a factory (possibly with window and door frames included), transported to the site, lifted into place by a crane and bolted or chemical material together.