An eyebrow is the area above your eyes where hair grows. It's also called the brow.
When we talk about someone's brow, we usually mean their face or forehead. For example, if you have a big worry on your mind, people might say "Don't furrow your brow" - that means don't wrinkle up your forehead. In some cases, when artists draw faces, they need to pay attention to the shape of the brow. It's also common for people to refer to the brow ridge as part of their facial structure.
The ridge over the eyes; the eyebrow.
To bound or limit; to be at, or form, the edge of.
