If you're thinking that an income is basically anything you earn, right? You're right.

But do we treat all income with equal respect?

Most people equate only a salary with income. This definition is unbalanced as it does not consider people who earn their primary income via freelancing, business, contractual work, and so on.

Any inflow of money is an income and you need to treat it like that; as the stepping stone to managing your finances.