The Collaborative International Dictionary of English v.0.48:

Turnpike \Turn"pike`\, n. [Turn + pike.]
   1. A frame consisting of two bars crossing each other at
      right angles and turning on a post or pin, to hinder the
      passage of beasts, but admitting a person to pass between
      the arms; a turnstile. See Turnstile, 1.
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            I move upon my axle like a turnpike.  --B. Jonson.
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   2. A gate or bar set across a road to stop carriages,
      animals, and sometimes people, till toll is paid for
      keeping the road in repair; a tollgate.
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   3. A turnpike road. --De Foe.
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   4. A winding stairway. [Scot.] --Sir W. Scott.
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   5. (Mil.) A beam filled with spikes to obstruct passage; a
      cheval-de-frise. [R.]
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   Turnpike man, a man who collects tolls at a turnpike.

   Turnpike road, a road on which turnpikes, or tollgates, are
      established by law, in order to collect from the users
      tolls to defray the cost of building, repairing, etc.
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