The Collaborative International Dictionary of English v.0.48:

Cringle \Crin"gle\ (kr[i^][ng]"g'l), n. [Icel. kringla orb; akin
   to kring around, and to D. kring circle, and to E. cringe,
   crank.]
   1. A withe for fastening a gate.
      [1913 Webster]

   2. (Naut.) 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.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cringle
    n 1: fastener consisting of a metal ring for lining a small hole
         to permit the attachment of cords or lines [syn: cringle,
         eyelet, loop, grommet, grummet]

Moby Thesaurus II by Grady Ward, 1.0:

48 Moby Thesaurus words for "cringle":
   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