Syntax is the order in which words and phrases are put together, such as a URL (web address) which consists of several phrases that are strung together to define a location or service on the Internet. A syntax error occurs when a user (or programmer) has put words in an order that a program does not understand. A syntax error while surfing the Web may be caused by a mistyped or inadvertently rearranged URL, making it incomprehensible to a web browser.