Profit is revenue minus everything: wages, rent, materials, marketing, interest and tax. It's the bottom line, and it's what actually belongs to shareholders.
A company can be enormous and unprofitable, or modest and very profitable. Amazon spent years deliberately choosing the first while it built out warehouses.
Profit can also swing on one-off events — a legal settlement, a factory sale, a write-down. That's why investors look at several years rather than one.