Profit (Gewinn) is how much money you make after expenses. Profit is not the same as revenue (Umsatz).
For example, if you have a product that costs 6€ to make, and you sell it for 10€, your profit is 4€ per sale. If you sell 100 units, your total revenue is 1,000€, but your profit is only 400€. The other 600€ are your business expenses.
You only pay income tax and trade tax on your profit, not your income.