Startup = Growth
A startup is a company designed to grow fast, not just a new business.
Explanation
Paul Graham's definition: what makes a startup different from other new businesses is growth rate. Startups aim for 5-7% weekly growth, reaching thousands or millions of users. This growth focus changes everything—from hiring to product decisions to fundraising. Without growth, you're just a small business (which is fine, but different).
Real-World Example
Facebook grew from one college to all colleges to everyone. Uber grew from San Francisco to every major city. Airbnb grew from air mattresses in San Francisco to millions of global listings. These companies were designed for rapid expansion, not steady local growth like a restaurant or consulting firm.
How to Apply
Set and track weekly growth targets (5-7% is good). Growth can be users, revenue, or engagement—pick one primary metric. Design everything for growth: viral features, referral programs, word-of-mouth mechanics. If you can't grow fast, consider whether you're building a startup or a lifestyle business. Both are valid, but require different approaches.