Source: Apartment Therapy —
A modular home is a house that is built in a factory and moved to its building site in sections. Once there, the sections are connected and the home is placed on a permanent foundation.
At the same time, these properties can often referred to as prefabricated or pre-fab homes. This terminology can be confusing, because manufactured and mobile homes are also prefabricated and built in a factory before being moved to the job site. The terms “modular home” and “manufactured home” are also commonly used interchangeably, even though they are built differently and are subject to different regulations.