Stench trap

from The Collaborative International Dictionary of English v.0.48

Stench \Stench\, n. [AS. stenc a strong smell, fr. stincan. See
   {Stink}, v. i.]
   1. A smell; an odor. [Obs.]
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            Clouds of savory stench involve the sky. --Dryden.
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   2. An ill smell; an offensive odor; a stink. --Cowper.
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   {Stench trap}, a contrivance to prevent stench or foul air
      from rising from the openings of sewers, drains, etc.
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