Grommet

1. (n.) A ring formed by twisting on itself a single strand of an unlaid rope; also, a metallic eyelet in or for a sail or a mailbag. Sometimes written grummet.

2. (n.) A ring of rope used as a wad to hold a cannon ball in place.

Thesaurus Entries

air hole, annulet, armhole, blowhole, bullet-hole, bunghole, circlet, cringle, deadeye, eye, eyelet, gasket, guide, keyhole, knothole, loop, loophole, manhole, mousehole, peephole, pigeonhole, pinhole, placket, placket hole, porthole, punch-hole, ringlet, roundlet, spiracle, tap, vent, venthole