From Longman Business Dictionary
panelpan·el /ˈpænl/ noun [countableC]1a group of people chosen to give advice or decide somethingAn advisory panel will review new data on the safety of the products.
→ consumer panel → selection panel → takeover panel2MARKETING in market research, a group of people chosen to discuss particular products so that changes can be made to them or to the way they are soldThese findings are backed up by the panel research I mentioned earlier.