clues

A strand of yarn etc. as used to guide one through a labyrinth; something which points the way, a guide.

Information which may lead one to a certain point or conclusion.

An object or a kind of indication which may be used as evidence.

Insight or understanding ("to have a clue [about]" or "to have clue". See have a clue, clue stick)

To provide with a clue.

“The crossword compiler wasn't sure how to clue the word "should".”

To provide someone with information which he or she lacks (often used with "in" or "up").

“Smith, clue Jones in on what's been happening.”