1. a ring or eyelet of metal, plastic, or rubber used to reinforce a hole or protect a cord or cable passing through it
Usage: common in nautical, industrial, and general hardware contexts
2. a young surfer or skateboarder
Usage: informal; chiefly Australian and New Zealand slang

Examples

• The tent's grummet tore when we pulled the rope too hard.
• She threaded the cable through the grummet in the desk to keep it organized.
• The sail was reinforced with brass grummets at each corner.
• A young grummet was learning to surf at the beach.
• The grummets gathered at the skate park after school.