An exhibitor is a person or a company that shows something to the public at an organised event. At a trade fair, the companies renting booths and displaying their products are the exhibitors; the people walking around looking are the visitors or attendees. At an art show, the artists whose paintings hang on the wall are exhibitors. At an agricultural or dog show, the people entering their animals for judging are also called exhibitors. It is an event-organiser's word — you meet it on signs, badges, forms and websites: "exhibitor registration," "exhibitor list," "exhibitors' entrance." Ordinary people rarely say it in conversation; they would say "the companies at the show" or name the company. Note that the exhibitor is the one displaying, not the one who owns the venue and not the museum staff — though a museum or cinema can itself be an exhibitor in the trade sense, since in the film business the cinema chains that actually screen films are called exhibitors.