The Thread Hidden Inside a “Clue”
When detectives discover a clue, they are—linguistically speaking—picking up a ball of thread.
The word clue began as clew, an Old English word meaning “a ball of thread or yarn.” Its transformation was inspired by the Greek myth of Theseus and the Minotaur.
Theseus entered the Labyrinth to kill the terrifying creature, but defeating it was only half the problem: he also had to escape the maze. Ariadne gave him a ball of thread, which he unwound as he walked. After killing the Minotaur, he followed the thread back to the entrance.
Because the thread guided Theseus through a confusing maze, clew gradually acquired a figurative meaning: anything that guides someone through a difficult problem. During the 17th century, the spelling clue emerged and eventually became standard for a piece of evidence. The original spelling, clew, survives mainly as a nautical term.
So every detective following a trail of clues is metaphorically doing exactly what Theseus did—following a thread through a labyrinth until the truth appears. Merriam-Webster
