Prefer the term Category to our default Campaign? You can change the word Campaign with the Languages & Strings tool (all licenses).
How do I use Languages and Strings to rename Campaigns?
1) Go to Community Settings>>Customization>>Languages & Strings
2) Uncheck the 'Regex' checkbox , Put the desired word 'in 'Filter' and Click 'Refresh'
3) There are 15 instances of the word Campaign spread throughout the site. Use your browser's search tool to locate all instances of the word category.
4) Then customize all of the strings by checking each string's "Customized" check box and modifying the string. After modifying click on 'Save' button:
5) Refresh your browser to see the changes.