Source : Webster's Revised Unabridged Dictionary (1913)

Pin \Pin\, v. t. [imp. & p. p. {Pinned}; p. pr. & vb. n.
   {Pinning}.] [See {Pin}, n.]
   To fasten with, or as with, a pin; to join; as, to pin a
   garment; to pin boards together. ``As if she would pin her to
   her heart.'' --Shak.

   {To pin one's faith upon}, to depend upon; to trust to.