Income is defined by the Courts as corporate profits.
Compensation for labor is a common law right to "pursuit happiness" discussed in the Declaration of Independence where it talks about "life, liberty, and the pursuit of happiness".
The right to pursue happiness is the right to get compensation for labor because none of us are happy if we cannot eat. Our right to pursue happiness is the right to do things that make money by getting compensation for labor.
In the early statutes, prior to the civil war they talk about compensation for labor for government employees.
Income tax was originally called the kickback tax for government employees and it is still the same today.
This video provides some ideas about how to arrange your affairs so you are exercising your right to "pursue happiness" by getting "compensation for labor".