A strand of yarn etc. as used to guide one through a labyrinth; something which points the way, a guide.
"The old tapestry served as a clue, winding its colorful threads like a path through the maze of history."
In plain English: A clue is any piece of information that helps you figure something out.
"I have no clue where my keys are hiding today."
Usage: Use "clue" when referring to information or evidence that helps solve a problem or mystery. Avoid using it to mean a labyrinth's guiding thread, as this sense is outdated.
To provide with a clue.
"The detective offered a crucial clue to help solve the mystery."
The word clue is a variant of clew, originally meaning "a ball of thread or yarn." Its modern sense comes from the story of Theseus using such a string as a lifeline while navigating the Labyrinth to defeat the Minotaur.