You could use other definitions, such as picking an arbitrary number of years and call anything younger than that a startup. But maintaining a high growth explains so many aspects of a startup's life (why founders give up parts of their company to investors, why most are focused in technology etc) that it seems any other way of looking at it would be misleading at best. Why would a 6-month restaurant be called a startup if it's not designed ever to scale beyond its neighborhood, or why would you no longer call a startup something that keeps growing weekly at 5%?
>> If you want to understand startups, understand growth. Growth drives everything in this world. Growth is why startups usually work on technology—because ideas for fast growing companies are so rare that the best way to find new ones is to discover those recently made viable by change, and technology is the best source of rapid change. Growth is why it's a rational choice economically for so many founders to try starting a startup: growth makes the successful companies so valuable that the expected value is high even though the risk is too. Growth is why VCs want to invest in startups: not just because the returns are high but also because generating returns from capital gains is easier to manage than generating returns from dividends. Growth explains why the most successful startups take VC money even if they don't need to: it lets them choose their growth rate. And growth explains why successful startups almost invariably get acquisition offers. To acquirers a fast-growing company is not merely valuable but dangerous too. <<
No matter how many paragraphs one quotes from Paul Graham, it is very hard for an argument to evade the reality that the word "startup" was used in other ways before he wrote this essay.
It's common for people to have discovered a new concept intuitively without understanding all its implications. Like Newtonian physics. Aiming to redefine it properly is worthy.
>> If you want to understand startups, understand growth. Growth drives everything in this world. Growth is why startups usually work on technology—because ideas for fast growing companies are so rare that the best way to find new ones is to discover those recently made viable by change, and technology is the best source of rapid change. Growth is why it's a rational choice economically for so many founders to try starting a startup: growth makes the successful companies so valuable that the expected value is high even though the risk is too. Growth is why VCs want to invest in startups: not just because the returns are high but also because generating returns from capital gains is easier to manage than generating returns from dividends. Growth explains why the most successful startups take VC money even if they don't need to: it lets them choose their growth rate. And growth explains why successful startups almost invariably get acquisition offers. To acquirers a fast-growing company is not merely valuable but dangerous too. <<