A grommet is a small ring, usually made of metal, rubber, or plastic, that reinforces a hole in fabric, leather, or other material. You've probably seen grommets at the top of a shower curtain, where they protect the fabric from tearing when you slide the hooks through. Sneakers often have grommets around the lace holes, and tarps use them at their corners so you can tie them down without ripping the material.

Without grommets, holes in fabric would quickly fray and tear from repeated use. The grommet spreads out the stress on the material, making the hole much stronger and longer-lasting. Installing a grommet involves punching or cutting a hole, then pressing or hammering the ring into place so it grips the material firmly on both sides.

In sailing and surfing communities, people sometimes use grommet (or grom) as slang for a young, enthusiastic beginner, though this meaning is unrelated to the reinforcing ring.