A rubber grommet is a small, round piece made of rubber that is used to protect and cover holes or edges in various objects. It is often inserted into holes to prevent damage and provide a cushioning effect. Full definition
It charges via Lightning, with a little rubber grommet on top to cover the hole. (theverge.com)
Hi there - I believe the «gasket» you mention that is actually leaking is one of a handful of rubber grommets for the bolts that hold on the valve cover gasket. (yourmechanic.com)
The Revolution helmet by Riddell, an NFL helmet maker, attenuates some of that force through rubber grommets built into the face - mask mounts. (discovermagazine.com)