principalclient
nounUK /ˈprɪn.sə.pəl ˈklaɪ.ənt/
US /ˈprɪn.sə.pəl ˈklaɪ.ənt/
A principal client is the main person who pays for and works with a company.
The builder met with his principal client to plan the new house.
OTHER MEANINGS
2. The most important buyer in a business deal.
The shop gave its principal client a special discount.
3. A person who hires a professional and is the main one in charge.
The lawyer called her principal client before the meeting.
4. The leading customer of a company over a long time.
Their principal client has worked with them for ten years.