When someone mentions Wall Street, most people think of stocks and bonds. Stocks represent equity, or outright ownership in a company. Bonds, in contrast, represent debt or loan. An investor who buys bonds of a corporation or government unit simply lends it money, and no ownership is involved.
Corporations that need to raise capital have a choice: they can either issue stock, thereby increasing their equity, or they can issue bonds, increasing their debt. When a government needs to raise money for public works such as building schools, hospitals, museums, roads, sanitation systems, etc., they can’t issue stock. Instead, they issue bonds which represent loans.