Thick board, literally?

TWOFOUR is a 7-letter word and the answer to the crossword clue "Thick board, literally?" The question mark is a signal from the puzzle constructor that this clue involves a pun, double meaning, or lateral wordplay. Rather than defining TWOFOUR directly, the clue approaches the answer from an unexpected angle. When you see a question mark at the end of a clue, resist the obvious reading and look for the twist.

See all clues for the answer TWOFOUR.