What does the word eyebrow mean?

Usage examples for eyebrow

  1. The sheriff cocked an eyebrow at the two men. –  by
  2. The arch of each eyebrow, defined by a thin down of hair, surrounded the tortoise- shell rim of the glasses and made a couple of circles as it were, slightly apart. – Modeste Mignon by Honore de Balzac
  3. I must have lifted an eyebrow, for Lucy said: Yes. – We Three by Gouverneur Morris