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.

Source : WordNet®

pin
     n 1: a piece of jewelry that is pinned onto the wearer's garment
     2: when a wrestler's shoulders are forced to the mat [syn: {fall}]
     3: small markers inserted into a surface to mark scores or
        define locations etc. [syn: {peg}]
     4: a number you choose and use to gain access to various
        accounts [syn: {personal identification number}, {PIN
        number}]
     5: informal terms of the leg; "fever left him weak on his
        sticks" [syn: {peg}, {stick}]
     6: axis consisting of a short shaft that supports something
        that turns [syn: {pivot}]
     7: cylindrical tumblers consisting of two parts that are held
        in place by springs; when they are aligned with a key the
        bolt can be thrown
     8: flagpole used to mark the position of the hole on a golf
        green [syn: {flag}]
     9: a small slender (often pointed) piece of wood or metal used
        to support or fasten or attach things
     10: a holder attached to the gunwale of a boat that holds the
         oar in place and acts as a fulcrum for rowing [syn: {peg},
          {thole}, {tholepin}, {rowlock}, {oarlock}]
     11: a club-shaped wooden object used in bowling; set up in
         groups as a target [syn: {bowling pin}]
     [also: {pinning}, {pinned}]

pinning
     n : a mutual promise of a couple not to date anyone else; on
         college campuses it was once signaled by the giving of a
         fraternity pin

pin
     v 1: to hold fast or prevent from moving; "The child was pinned
          under the fallen tree" [syn: {trap}, {immobilize}, {immobilise}]
     2: attach or fasten with pins [ant: {unpin}]
     3: pierce with a pin; "pin down the butterfly"
     4: immobilize a piece
     [also: {pinning}, {pinned}]

pinning
     See {pin}