A cipher, on the other hand, is a message in which letters or symbols replace the actual letters in the message. Every cipher has a "key"—information used to decipher a message.

And the symbols, which range from geometric designs to representations of fish or jars, have also been found on signs, tablets, copper plates, tools, and pottery.

King Charles III's royal cipher was unveiled on Monday, Sept. 26, revealing the monogram for the United Kingdom's new monarch. The king's cipher is a monogram consisting of his first name initial ...