Pin is a word with multipe meanings:

• A pin is a device used for fastening objects or material together. It is usually made of steel, and is formed by drawing out a thin wire, sharpening the tip, and adding a head. Someone whose trade is making pins is called a pinner.
  • Thumbtacks and badges are types of pins.
• In electronics a pin is an electric interconnection. For example a metal wire coming out of an Integrated circuit or Transistor.
• The term pin is used in multiple sports and strategy games:
  • In bowling, pins must be knocked down by the bowling ball
  • In chess, pin refers to preventing a piece from moving by threatening the king
  • In Sport wrestling, pinning is a way of winning a match
• In firearms, the firing pin is a nail-like device to transfer hammer energy to the primer of ammunition
• Pin , a commune of the Haute-Saône département, in France
• Operation Pin is an international policing initiative to find pedophiles using the internet to access child pornography.

• PIN is also used as an acronym for
  • Personal Identification Number
  • Postal Index Number (India)