A bond is a debt security issued by corporations, municipalities, states, and governments to raise capital. When an investor purchases a bond, they are essentially lending money to the issuer in exchange for periodic interest payments and the return of the bond's face value (principal) at maturity. Bonds are often referred to as fixed-income securities because they provide regular interest payments, known as coupon payments.
Bonds can vary widely in terms of maturity (short-term, medium-term, long-term), credit quality (investment-grade, high-yield), and type (government, municipal, corporate). The interest rate (coupon rate) and creditworthiness of the issuer determine the bond's attractiveness to investors. Bonds are a key component of diversified investment portfolios, providing income and reducing overall portfolio risk compared to stocks.