The answer to the crossword clue 'Heading for half of crossword clues' is DOWN, with four letters. The term 'DOWN' is used in crosswords to indicate that the answer to the clue should be written downwards in the grid. It is the opposite of the term 'ACROSS', which indicates that the answer should be written ACROSS the grid. DOWN clues are usually placed on the left side of the grid, while ACROSS clues are placed on the top.