Escrow is a legal concept in which a financial instrument or an asset is held by a third party on behalf of two other parties that are in the process of completing a transaction. The funds or assets are held by the escrow agent until it receives the appropriate instructions or until predetermined contractual obligations have been fulfilled. Money, securities, funds, and other assets can all be held in escrow.
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For example, the both of us will be having a deal, let's say I am gonna buy something from you, instead of directly giving you the payment, I'll give it first to the escrow (a person that both of us trusts), after I successfully received the item you are selling, the escrow will then give you my payment.
Or what we also call, MIDDLEMAN.