The Collaborative International Dictionary of English v.0.48:

Roar \Roar\, v. i. [imp. & p. p. Roared; p. pr. & vvb. n.
   Roaring.] [OE. roren, raren, AS. r[=a]rian; akin to G.
   r["o]hten, OHG. r[=e]r[=e]n. [root]112.]
   1. To cry with a full, loud, continued sound. Specifically:
      (a) To bellow, or utter a deep, loud cry, as a lion or
          other beast.
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                Roaring bulls he would him make to tame.
                                                  --Spenser.
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      (b) To cry loudly, as in pain, distress, or anger.
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                Sole on the barren sands, the suffering chief
                Roared out for anguish, and indulged his grief.
                                                  --Dryden.
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                He scorned to roar under the impressions of a
                finite anger.                     --South.
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   2. To make a loud, confused sound, as winds, waves, passing
      vehicles, a crowd of persons when shouting together, or
      the like.
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            The brazen throat of war had ceased to roar.
                                                  --Milton.
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            How oft I crossed where carts and coaches roar.
                                                  --Gay.
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   3. To be boisterous; to be disorderly.
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            It was a mad, roaring time, full of extravagance.
                                                  --Bp. Burnet.
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   4. To laugh out loudly and continuously; as, the hearers
      roared at his jokes.
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   5. To make a loud noise in breathing, as horses having a
      certain disease. See Roaring, 2.
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   Roaring boy, a roaring, noisy fellow; -- name given, at the
      latter end Queen Elizabeth's reign, to the riotous fellows
      who raised disturbances in the street. "Two roaring boys
      of Rome, that made all split." --Beau. & Fl.

   Roaring forties (Naut.), a sailor's name for the stormy
      tract of ocean between 40[deg] and 50[deg] north latitude.
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The Collaborative International Dictionary of English v.0.48:

Roaring forties \Roar"ing for"ties\ (Naut.)
   The middle latitudes of the southern hemisphere. So called
   from the boisterous and prevailing westerly winds, which are
   especially strong in the South Indian Ocean up to 50[deg] S.
   [Webster 1913 Suppl.]