Profit
It is, in other words, the money that is left when you take away all your costs from the money that comes in.
So for instance if you have total revenues of £10,000 but against that you have total costs (such as salaries and so on, heating, electricity, stock costs) for the month that come to £8,000 then this leaves you with £2,000 at the end of that period.
That £2,000 is your profit. Whether you get to keep it all depends on various factors such as your country, and whether you have nasty things like corporation tax to pay if you are a company.
Related Articles
CondominiumMoney
Mortgage
Dutch auction
I-Bonds