The following list indicates words you must not use for ColdFusion variables, user-defined function names, or custom tag names. Although you can safely use some of these words in some situations, you can prevent errors by avoiding them entirely.

• Any name starting with cf. However, when you call a CFML custom tag directly, you prefix the custom tag page name with cf_.
• Built-in function names, such as Now or Hash
• Scope names, such as Form or Session
• Operators, such as NE or IS
• The names of any built-in data structures, such as Error or File
• The names of any built-in variables, such as RecordCount or CGI variable names
• CFScript language element names such as for, default, or continue

Remember that ColdFusion is not case-sensitive. For example, all of the following are reserved words: IS, Is, iS, and is.