A business partner or client company; a customer or trading partner with whom transactions are conducted.
新しい取引先と今週中に取引を開始する予定です。
We plan to start transactions with a new client this week.
この取引先は海外に多くの支店を持っている。
This business partner has many branches overseas.
取引先への納品は来週中に完了させてください。
Please complete the delivery to the client by next week.