What is "clew-line block"

Clew \Clew\ (kl[=u]), Clue \Clue\, n. [OE. clewe, clowe, clue, AS. cleowen, cliwen, clywe ball of thread; akin to D. kluwen, OHG. chliwa, chliuwa, G. dim. kleuel, kn["a]uel, and perch. to L. gluma hull, husk, Skr. glaus sort of ball or tumor. Perch. akin to E. claw. [root]26. Cf. Knawel.]

1. A ball of thread, yarn, or cord; also, The thread itself.

   Untwisting his deceitful clew.
   --Spenser.

2. That which guides or directs one in anything of a doubtful or intricate nature; that which gives a hint in the solution of a mystery.

   The clew, without which it was perilous to enter the vast and intricate maze of countinental politics, was in his hands.
   --Macaulay.

3. (Naut.) (

   1. ) A lower corner of a square sail, or the after corner of a fore-and-aft sail. (

   2. ) A loop and thimbles at the corner of a sail. (

   3. ) A combination of lines or nettles by which a hammock is suspende

   4. Clew garnet (Naut.), one of the ropes by which the clews of the courses of square-rigged vessels are drawn up to the lower yards.

      Clew line (Naut.), a rope by which a clew of one of the smaller square sails, as topsail, topgallant sail, or royal, is run up to its yard.

      Clew-line block (Naut.), The block through which a clew line reeves. See Illust. of Block.