Flavor is the way something tastes. If an ice cream shop offers 50 flavors, each one of them will taste different.
The flavor of your soup can be adjusted by adding salt — and when you add ingredients to change a food's taste, you can say you flavor it. From the flavor of food comes the sense of flavor meaning "atmosphere" or "feeling." You could say, for example, that you're not crazy about a particular clothing shop because it has such a glitzy, expensive flavor. Flavor initially meant "smell," from the Vulgar Latin flator, "odor."