Wiki syntax is a markup language used in a wiki web page. (For a broader overview of wiki syntax, please see Why Wiki Syntax Is Important.) To avoid requiring users to learn HTML, wiki syntax uses common characters in uncommon ways (or character combinations that are not normally used together) and provides them with a special meaning. Some of the character combinations only work at the beginning of a line, while others can be inserted anywhere in the text and are active until a closing combination of characters is met.

Wiki syntax uses a character repeated twice for most functions, but it also has a few two-character combinations. With a two-character combination, the characters are reversed to turn off the function. Monospaced text provides a good example of this; the minus (-) and plus (+) characters are used to start the using monospaced text and plus (+) and minus (-) characters specify the end of it.