CRYPTS' A crypt is a type of crossword clue that involves solving a word or phrase by substituting letters for numbers. The letters are usually arranged in a symmetrical pattern, and the solver must use the given numbers to determine which letter goes in each space. Crypts can be very challenging, as the solver must figure out the pattern of the letters and the meaning of the words or phrases. Crypts are often used in crosswords to add an extra layer of difficulty.