The Collaborative International Dictionary of English v.0.48:

Fence \Fence\ (f[e^]ns), n. [Abbrev. from defence.]
   1. That which fends off attack or danger; a defense; a
      protection; a cover; security; shield.
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            Let us be backed with God and with the seas,
            Which he hath given for fence impregnable. --Shak.
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            A fence betwixt us and the victor's wrath.
                                                  --Addison.
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   2. An inclosure about a field or other space, or about any
      object; especially, an inclosing structure of wood, iron,
      or other material, intended to prevent intrusion from
      without or straying from within.
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            Leaps o'er the fence with ease into the fold.
                                                  --Milton.
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   Note: In England a hedge, ditch, or wall, as well as a
         structure of boards, palings, or rails, is called a
         fence.
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   3. (Locks) A projection on the bolt, which passes through the
      tumbler gates in locking and unlocking.
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   4. Self-defense by the use of the sword; the art and practice
      of fencing and sword play; hence, skill in debate and
      repartee. See Fencing.
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            Enjoy your dear wit, and gay rhetoric,
            That hath so well been taught her dazzing fence.
                                                  --Milton.
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            Of dauntless courage and consummate skill in fence.
                                                  --Macaulay.
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   5. A receiver of stolen goods, or a place where they are
      received. [Slang] --Mayhew.
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   Fence month (Forest Law), the month in which female deer
      are fawning, when hunting is prohibited. --Bullokar.

   Fence roof, a covering for defense. "They fitted their
      shields close to one another in manner of a fence roof."
      --Holland.

   Fence time, the breeding time of fish or game, when they
      should not be killed.

   Rail fence, a fence made of rails, sometimes supported by
      posts.

   Ring fence, a fence which encircles a large area, or a
      whole estate, within one inclosure.

   Worm fence, a zigzag fence composed of rails crossing one
      another at their ends; -- called also snake fence, or
      Virginia rail fence.

   To be on the fence, to be undecided or uncommitted in
      respect to two opposing parties or policies. [Colloq.]
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