What is the Difference Between Similar But Different Things, Terms, and Objects

What is the Difference between Self Employment, Sales, Capital Gains, Income, Payroll, Withholding and Corporate Tax

Earning money is the need of every person to spend his life in reasonable way. There are several ways of earning money. Some people do job to make money, while some run their own businesses to earn money. Self Employment, Sales, Capital Gains, Income, Payroll, Withholding and Corporate Tax are the various terms used in this regard.