I usually get goose bumps once I hear "startup". The term has gotten so trendy now that students and lazy people spending too much time online define themselves as "startup owners" or "in the startup R&D phase of the next big thing". While there are plenty of incredible startups out there, the lack of too formal definition allows everyone to label themselves as a startup founder once they decide to do something.

It actually reminds me of the early years of blogging when lots of university students I knew were "Founder/Owner at {myblog.com}", since that was their huge accomplishment. Or novelists who spend years getting inspiration for their second best-seller.

Another part of the startup definition (according to Wikipedia) is:

"The latter implements a well-known existing business strategy whereas a start-up explores an unknown or innovative business model in order to disrupt existing markets, as in the case of Amazon, Uber or Google. "

While this is also vague to some extent, it's more structured compared to "a company, a partnership or temporary organization designed to search for a repeatable and scalable business model". My definition of startup is a person or a small team focused on growing fast and accomplishing great results in a shorter amount of time. The most important part though is that a startup has a unique selling proposition - a key thing that is truly innovative and groundbreaking, and could affect a large group of people or businesses in one way or another.

Creating yet another design or web development agency is not a startup if you offer the most generic services in the world.

That said, a plugin development process is not a startup per se. It's just building a plugin. On the other hand, if the plugin is truly innovative and has serious impact on a given niche, the founder/team focus on growth hacking, reaching out to the masses, partnering with other teams and integrating various services etc., it is a potential startup that could get traction and gain a massive user base.

That's at least my point of view.