'中介' literally combines '中' (zhōng, meaning 'middle' or 'in-between') and '介' (jiè, meaning 'to introduce' or 'to mediate'), forming a compound noun that refers to a person or organization acting as a go-between—facilitating communication, negotiation, or transactions between two or more parties. It emphasizes neutrality and bridging function, not authority or final decision-making.

This term is widely used in business, real estate, employment, and education contexts—for example, a real estate agency helping buyers and sellers, or a job placement service connecting employers and candidates. While '中介' can refer to individuals or companies, it often carries a slightly formal or institutional tone. Unlike casual terms like '介绍人' (introducer), '中介' implies an ongoing, structured role with possible fees or contractual obligations.