Intermediary (noun)

1. A person or thing that acts as a link between two people or groups.
2. A person or organization that acts as a go-between in a transaction or negotiation.

Origin:

Early 17th century: from medieval latin intermediarius, from latin intermedius "lying between", from inter- "between" + medius "middle".

Examples:

1. The company used an intermediary to negotiate the deal.
2. The intermediary helped to resolve the dispute between the two parties.
3. An intermediary is a person who helps to bring buyers and sellers together.
4. The bank acts as an intermediary in the transaction.
5. The intermediary is responsible for communicating between the two sides.