A startup, where each funding round is like a logical different startup, but uses the key component created in the previous funding round, as an enabler for the next round, often jumping to another industry in each round.
To realize a long-shot visions requiring funding of multiple breakthroughs, it is insufficient to focus narrowly on a single startup. A traditional approach is to either do it through strategic investment portfolio management (like ARK Invest), or to be a serial-entrepreneur, intelligently combining the startups into a purposeful group.
A third approach is "Multi-Business Startup": a startup, that connects multiple startup business ideas, that depend one on another into a sequence of funding rounds, where each funding round is a different business using technology of previous round business, rather than just a growth target with improved features and marketing ideas.
Example: If SpaceX had envisioned building Starlink before the SpaceX was even founded, as a next "funding round", it would be a "Multi-Business Startup". However, it focused on one thing, so it isn't, while Tesla, if it was a startup, could be considered a multi-business startup.
In other words, a "Multi-Business Startup" emulates a situation of gradually building a portfolio of startups with where success of one startup works as a technological foundation for another startup, and so on, and these startups interlink as dependencies to each other, are still the same company.
The catalytic effects achievable with "Multi-Business Startups" (such as multi-domain expertise, and motivation of people behind longer-shot visions) are likely not possible with traditional startups. The employees of such multi-business startups may be happier by being privileged to see the bigger picture, rather than being encapsulated within one unit that does its job well, and just serves the ecosystem, oblivious of a higher purpose, other than just to serve the ecosystem.
UPDATE: After a few searches on-line, I found that the idea of "Multi-Business Startup" is has been discussed in the 2021 paper: An Alternative to Lean Startup - Why and How startups can pursue multi-business strategie by master students Jesper Alm and John Lindblad at Chalmers University of Technology in Sweden. And, I came up with it, because I realized that the business plan that I'm preparing for realizing the HiveCell idea, turned out look like a "multi-business startup", because each round of funding would rely on a different business model to a different industry, yet all of them inter-dependent.