" . . . the ravel'd ___ of care": Macbeth

• Silken thread
• "The ravel'd ___ of care"
• Small silk thread
• " . . . the ravel'd ___ of care"
• "Sleep that knits up the ravell'd ___ of care": Shakespeare
• " . . . ravell'd ___ of care": Shak.

Wiktionary Word definitions in Wiktionary
n. 1 The knotted or entangled part of silk or thread. 2 Silk not yet twisted; floss. vb. (context weaving English) To separate, as threads; to divide, as a collection of threads.

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
"to separate or divide" (threads, strands, fibers), Old English -slæfan , from stem of -slifan "to separate, split, cleave," from Proto-Germanic *slifanan , perhaps related to the root of slip (v.). Compare German Schleife "a loop, knot, noose." Related: ...

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Sleave \Sleave\, v. t. [imp. & p. p. Sleaved (sl[=e]vd); p. pr. & vb. n. Sleaving .] To separate, as threads; to divide, as a collection of threads; to sley; -- a weaver's term.