From Wiktionary



  1. This symbol is placed in front of a number to mean that amount in dollars. When spoken, you would say "$X" as "X dollars", not "dollars X".
    That shirt costs $20.
  2. (informal) This symbol is sometimes used to replace the letter "S" as a way of bringing to mind money, wealth, or greed.
    Micro$oft Window$
  3. (computing) This symbol is short for cache.