First, they are used in different contexts. Wages, salary, and pay relate to individuals and the money they earn from working. Income relates to both individuals and companies. Revenue relates only to companies. Generally, they are used like this: Wage(two related uses: The amount of money someone who is paid by the hour receives per hour, such as $10 per hour. The total amount of the money earned by such a person over a period of time. His wages last month were $2000. Salary: the amount earned for each time period, by someone paid not by the hour. His salary is $50,000 a year. Pay: usually means the same as wages, but can sometimes to applied to salary, as well. His pay last month was $2000. Income: this is the trickiest one. For an individual, in a general sense, in means all inflows of money, from working and any other source. So if you had a salary of $50000 a year and received $10000 from your investment earnings, your income would be $60000. For an individual as related to taxes, the above would be called "gross income". You then get to subtract certain expenses, and calculate numbers such as "taxable income" For a business, the terms are used in a similar way. There is "gross income" which is all the money earned or received by the company. There is "net income" which is gross income minus expenses. Then there are other income calculations, as well. Revenue: this is very similar to "gross income" for a company. It measures inflows to a company, generally just from selling goods or services, but sometimes meaning inflows from all sources. It does not reflect any deductions for expenses, in most situations.

Wage, pay, salary and income are practically interchangeable when describing the amount of money someone earns (in a certain period). Revenue is generally used to describe the earnings of a company, an organisation, rather than an individual.