No. "Manufactured Home" has a specific, legal meaning in the USA. They are also referred to as "HUD Code" homes. "HUD Code" refers to the building code under which they are constructed. There are multi-section Manufactured Homes (informally called "double wides"), and single-section Manufactured Homes (informally called "single wides").
Manufactured Homes used to be called "Mobile Homes", and that term is still sometimes used, but it has no legal meaning; the last "Mobile Home" was built in 1976, before the HUD Code was codified.
"Modular Homes" also has a distinct meaning. Modular Homes are different than Manufactured Homes because they are built to different building codes - basically to whatever local or state building codes apply where the Modular Home will be sited. Modular Homes (informally, "Mods") are typically more expensive because they are generally fancier, but also because of the additional cost in constructing a home to varying (and usually more stringent) local and state building codes.
I'm a software developer, but I know a lot about this because my family owned a manufactured home dealership for four decades. And, I wrote and sell MH dealership management software.
I really wish a company would make modular homes that are actually modular, in that you could start with a 'tiny home' module, then a few years down the line add a 'bedroom and master bath' module and turn the original bedroom into a child's space, and so on. The end result might be at a premium over getting a big house all at once, but in the meantime you'd get the benefit of being able to invest most of your money instead of sinking it into a mortgage.
There'd be a lot of waste with that with pipes and electrical connections leading no where and at best lots of extra framing around the non existing doors that would be cut out to install the new section. There's also the issue of how to deal with the roof and cladding that would have to be sealed completely between the two sections against water and pests. It's doable but there's a lot of unavoidable work that'd have to be done to connect the two bits properly on top of whatever additional site preparation to extend the footprint of the foundation.
That work would be a big portion of the cost of adding on to a house much like additions are made now.
It would probably need to be constructed from standalone modules with something akin to an airlock to get between them. Even then whatever you save by buying piece-at-a-time might still end up more expensive than just building a bigger house and blocking off parts until you need them.
