Profit is how much money somebody (normally a company) makes. This is found by subtracting how much money they have spent (expenditure) from how much money they have brought in (revenue).
An example[change | change source]
If John spends $15 on some ice cream cones, and then sells them for $20, he has made a profit of $5. This is because he made $20 but when the $15 he used to buy the ice cream cones is subtracted, what is left is $5. In the end, he has $5 more than he had before he bought and sold the ice cream cones.