1 sth that is difficult to understand
ADJ. great | perplexing | scientific, theoretical
VERB + PUZZLE solve | remain What happened to the ship remains a puzzle.
PUZZLE + VERB remain The puzzle remains of what happened to the ship.
PREP. in a/the ~ They knew who the killer was, but there were still some gaps in the puzzle. | ~ about There is a puzzle about how the plant first came to Britain. | ~ of They're trying to solve the puzzle of how gravity works.
PHRASES a bit/piece of the puzzle Another piece of the puzzle fell into place. | the key to a puzzle Traces of explosives found among the wreckage were the key to the puzzle. | a piece in the puzzle The police didn't know what the message meant, but it was another piece in the puzzle. | a solution to a puzzle, something of a puzzle The origin of the word is something of a puzzle.
2 game that tests your skill, intelligence, etc.
ADJ. crossword, jigsaw | number, picture, word | complicated
VERB + PUZZLE do, solve
PUZZLE + NOUN book