Secret writing is a form of communication that involves the use of codes, symbols, and other methods to hide the meaning of a message. The three crossword solutions for the term secret writing are CODE (4 letters), RUNE (4 letters), and CIPHER (6 letters). A CODE is a system of words, letters, figures, or symbols used to represent a message. Runes are an ancient form of writing used by Germanic and Scandinavian cultures. A CIPHER is a type of CODE in which each letter of the message is replaced with another letter or symbol.