The Cashflow Quadrant is a way to categorize people based on where their money comes from: E, S, B, or I.
E stands for an Employee, someone who earns money by holding a job. S is Self-employed, earning money for themselves. B stands for Business, meaning someone who owns a company or system that generates money for them. And I is an Investor, someone who earns money from their various investments.
We all fall within at least one of these quadrants