stakeholder

Short definition from Wiktionary

Noun

1. 1
   A person holding the stakes of bettors, with the responsibility of delivering the pot to the winner of the bet.
2. 2
   A person such as a trustee, escrow agent or garnishee, who holds money or assets under trust for another party in a contractual agreement or as part of a claim.
3. 3
   A person or organisation with a legitimate interest (a stake) in a given situation, action or enterprise.