Is there a variable type that can hold > 4000 characters?

[jchavers]

Situation:
Report calls function, function is stored in oracle database, function gathers data to return to report.  Function has one parameter, this parameter is defined as a varchar2(4000) within the function, but I have recently come across situations where the data being gathered exceeds 4000 characters, causing the function to fail.  Is there a datatype that I can define in the function that can exceed 4000 characters in length that can be used to return the string to the report?

Thanks!