What is the meaning of the word "vested interest"?

Definitions:

  1. an interest in which there is a fixed right to present or future enjoyment and that can be conveyed to another copy to clipboard noun
    • I bequeathed my vested interests to my children upon my death. copy to clipboard
  2. groups that seek to control a social system or activity from which they derive private benefit copy to clipboard noun
    • Vested interests throw money at politicians to gain their favor in Washington. copy to clipboard