The Collaborative International Dictionary of English v.0.48:

Spile \Spile\ (sp[imac]l), n. [Cf. LG. spile, dial. G. speil,
   speiler, D. spijl. [root]170.]
   1. A small plug or wooden pin, used to stop a vent, as in a
      cask.
      [1913 Webster]

   2. A small tube or spout inserted in a tree for conducting
      sap, as from a sugar maple.
      [1913 Webster]

   3. A large stake driven into the ground as a support for some
      superstructure; a pile.
      [1913 Webster]

   4. (Mining) One of the thick laths or poles driven
      horizontally ahead on top of a set of the main timbering
      in advancing a level in loose ground.

   Syn: forepole; spill[2d].
        [RDH]

   Spile hole, a small air hole in a cask; a vent.
      [1913 Webster]