The Collaborative International Dictionary of English v.0.48:

Brow \Brow\ (brou), n. [OE. browe, bruwe, AS. br[=u]; akin to
   AS. br[=ae]w, bre['a]w, eyelid, OFries. br[=e], D. braauw,
   Icel. br[=a], br[=u]n, OHG. pr[=a]wa, G. braue, OSlav.
   br[u^]v[i^], Russ. brove, Ir. brai, Ir. & Gael. abhra, Armor.
   abrant, Gr. 'ofry`s, Skr. bhr[=u]. Cf. Bray a bank,
   Bridge.]
   1. The prominent ridge over the eye, with the hair that
      covers it, forming an arch above the orbit.
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            And his arched brow, pulled o'er his eyes,
            With solemn proof proclaims him wise. --Churchill.
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   2. The hair that covers the brow (ridge over the eyes); the
      eyebrow.
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            'T is not your inky brows, your brack silk hair.
                                                  --Shak.
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   3. The forehead; as, a feverish brow.
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            Beads of sweat have stood upon thy brow. --Shak.
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   4. The general air of the countenance.
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            To whom thus Satan with contemptuous brow. --Milton.
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            He told them with a masterly brow.    --Milton.
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   5. The edge or projecting upper part of a steep place; as,
      the brow of a precipice; the brow of a hill.
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   To bend the brow, To knit the brows, to frown; to scowl.
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