also: おおぐちこきゃく
major customer; large client
Refers to a customer or client that accounts for a significant portion of a business's sales or revenue. Common in business and sales contexts.
Our company renewed the contract with a major customer.
We provide special services to meet the needs of our large clients.
得意先 is a more general term for a regular customer or client, while 大口顧客 specifically emphasizes the large scale or importance of the customer.
重要顧客 means 'important customer' and may include strategic or key accounts, not necessarily defined by transaction volume alone, whereas 大口顧客 focuses on the size of business.
Standard kanji spelling. The reading おおぐちこきゃく is more common in modern business contexts.
Alternate reading; less common but still encountered. The おおぐち reading is preferred.
Compound of 大口 (おおぐち, 'large amount' or 'big mouth') and 顧客 (こきゃく, 'customer'). The term is straightforward and modern, with no obscure historical derivation.