Cringle

n. eye or loop on a boltrope of a sail for attachment of lines

A cringle is an eye through which to pass a rope. In nautical settings, the word refers to a small hole anywhere along the edge or in the corner of a sail, rimmed with stranded cordage and worked into the . Typically it encloses a metal grommet for reinforcement and to reduce wear. In this context, cringle and grommet coincide enough that the two are sometimes used interchangeably.
See more at Wikipedia.org...

Noun
1. fastener consisting of a metal ring for lining a small hole to permit the attachment of cords or lines
(synonym) eyelet, loop, grommet, grummet
(hypernym) fastener, fastening, holdfast, fixing

(n.)
An iron or pope thimble or grommet worked into or attached to the edges and corners of a sail; -- usually in the plural. The cringles are used for making fast the bowline bridles, earings, etc.
  

(n.)
A withe for fastening a gate.
  

Synonyms and related words:
air hole, armhole, blowhole, boltrope, bullet-hole, bunghole, canvas, clew, cloth, crowd of sail, deadeye, earing, eye, eyelet, foot, fore-and-aft sail, gasket, grommet, guide, head, keyhole, knothole, leech, loop, loophole, luff, manhole, mousehole, muslin, peephole, pigeonhole, pinhole, placket, placket hole, plain sail, porthole, press of sail, punch-hole, rag, reduced sail, reef point, reefed sail, sail, spiracle, square sail, tap, vent, venthole,