To ravel means to tangle or become tangled into a confused, knotted mess. When yarn ravels, it twists into snarls that are hard to undo. If you pull carelessly at a loose thread on your sweater, it might ravel into a frustrating knot instead of coming free cleanly.

Here's where things get confusing: ravel can also be used to mean almost the opposite. To ravel something can mean to untangle it, to separate the twisted threads and smooth them out. You might ravel out a knot in your shoelaces, carefully working the loops free.

How can one word seem to mean both tangling and untangling? The answer lies in context and sometimes in added words. When you say something ravels on its own, it usually means it's getting tangled. When you ravel out something deliberately, you're usually working to untangle it.

Many people use unravel instead to avoid confusion. If a mystery unravels, it comes apart and becomes clear. If a plan unravels, it falls to pieces. Unravel almost always means things coming undone or apart, while ravel keeps both ideas alive in the same word.