In current usage, a startup means a new business that is designed to scale rapidly. (Most don't actually manage to, but they're at least intended to.) It would be inconvenient if people started using the word to describe new businesses generally, because then we'd need to invent a new word for the subset designed to scale rapidly.
That's about as precise as most dictionary definitions. It doesn't mean the actual meaning of the word is that broad, just that dictionaries don't go into excessive detail.
There seems to be varying opinions on what a startup actually is. Some definitions focus on the ability to rapidly scale, while others emphasize the fragility of startups. For instance, Eric Ries, author of The Lean Startup, defines a startup as "a human institution designed to deliver a new product or service under conditions of extreme uncertainty." This definition would tend to include almost every new business, while your definition of a startup would only include those which are structured for rapid growth. Maybe I'm being a bit too pedantic, but it seems the word "startup" is being used so inconsistently nowadays that it has lost a bit of its meaning.
The problem lies in the definition of "new" and "extreme". Both are very loose.
In the standard Techcrunch definition of "new", and "extreme", "new" is "new" and hasn't been done successfully before (or at least in the reach of the startup in question).
And "extreme uncertanty" usually means: you have a burn rate which forces you to rapidly achieve product-market fit, pivot, get more money, or give up. The above definition of "new" adds up to the "extreme uncertanty", as you are not sure what you are currently doing is something people want, and even if you pivot into something else, you will not be sure about it as well.
Therefore, a new old' fashioned bakery is a new business, but it is not doing something "new", neither has "extreme uncertainty" attached to it.
Yes, but won't that new old' fashion bakery still have "extreme uncertainty" in its successful outlook, especially in today's dire economic conditions?
PG I actually thought about my article heading a lot and went back and fort between lifestyle "startups, businesses and entrepreneurs" for the right word to describe my post. At the end I decided on startups since the other two words are further off what I intended to convey. But I definitely can see your point and how it can become confusing.
A lifestyle business is a particular type of business, and a startup is another distinct type. They each have different requirements and business models, just as either one is different from a large public corporation.
Most of the Silicon Valley startup infrastructure is basically extraneous to a lifestyle business. Incubators, angel investors, VCs, all the other support pieces built for rapid growth -- all of that is geared toward businesses that have a chance of getting huge and IPOing and giving back a huge return to everyone who helped it along.
With a lifestyle business, by contrast, you tend to self-finance, you shepherd your cash and investments carefully, and if you need to expand, you might go talk to your bank about a line of credit and show them your cash flow and consistent returns to date in order to help secure it.
Lifestyle businesses can be great. My dad has a successful retail store, a low-stress environment, a great house, and plenty of time to enjoy it all. We should all be so lucky. They're just not the same thing as startups.