"Revenue" is the money that a company or a person makes from its customers. When you're talking about money, there are several terms that all have different meanings:

• Revenue is the money that a business gets from sales, or from investments.
• Income is also money that a company makes. This word is also used to describe the amount of money that an individual person makes.
• Profit is the amount of money that is left after a company pays for its employees, materials, rent, and other costs.

There are much more technical definitions for each of these terms that accountants and business executives need to learn, but these definitions will work for most people.

You can use either "revenue" as an uncountable noun, or "revenues":

Revenues are pretty good this quarter.