When young children, especially girls, wake from an evening's slumber with tangles and snarls in their hair, mothers with a tradition of fairy folklore might whisper to their daughters that they had caught fairy locks or elf-locks. Faeries, they say, tangled and knotted the hairs of the sleeping children as they played in and out of their hair at night.[1]
Shakespeare references such elflocks in Romeo and Juliet in Mercutio's speech of the many exploits of Queen Mab, where he seems to imply the locks are only unlucky if combed out.[2]
Therefore, the appellation of elf lock or fairy lock could be attributed to any various tangles and knots of unknown origins appearing in the manes of beasts or hair of sleeping children.
It can also refer to tangles of elflocks or fairy-locks in human hair. In King Lear, Edgar impersonates a madman, "he elfs all his hair in knots."[3](Lear, ii. 3.) What Edgar has done, simply put, is to make a mess of his hair.