From Longman Dictionary of Contemporary Englishpiece of the puzzlepiece of the puzzleINFORMATIONa piece of information that helps you to understand part of a difficult question, mystery etc → puzzle
Examples from the Corpus
piece of the puzzle• It's another piece of the puzzle.• Take me out of there, and you're taking away a big piece of the puzzle.• The final pieces of the puzzle had now been slotted into place.• Fortunately, the next step in the research process supplied the missing piece of the puzzle.• So he created a temporary scaffolding to get one piece of the puzzle going.• How television has changed is one piece of the puzzle.• But what about the piece of the puzzle we have so far omitted?• All the pieces of the puzzle were in place: it was time for a little conference. 