A rivet is a metal fastener, a bolt-like device that holds together two pieces of metal or fabric. The round metal fasteners on your favorite pair of jeans are rivets.
Older buildings with metal frames like the Eiffel Tower are held together with rivets, and so are some bridges and military vehicles. Furniture upholstery often involves rivets, too. When you use a rivet to fasten, you can say you rivet — and similarly, to hold attention or captivate is also to rivet. The Old French root is river, "to clench or fasten."