A business or person that buys and sells goods, securities, or services as an intermediary or for their own account. Often used in financial and commercial contexts.
A securities broker mediates the buying and selling of stocks.
彼は中古車の取引業者として長年働いている。
He has worked for many years as a used-car dealer.
仲買人 is a more specific term for a broker or middleman, often in commodity markets, while 取引業者 is a broader term for any trading business.
ディーラー is a loanword often used for dealers in specific contexts like car dealerships or casino dealers, whereas 取引業者 is a native Japanese term covering a wider range of trading businesses.
Compound of 取引 (とりひき, 'transaction, dealing') and 業者 (ぎょうしゃ, 'business operator, trader').