Thread:1234HI5678/@comment-8-20191230214856/@comment-8-20200303022956

Categories exist when they have pages in them. So to delete a category, you just need to remove it from each page that currently contains it.

If you have edited the category page itself, you will need to delete it that way too - that's just a case of selecting the deletion option on the editing drop-down, just as you do for article pages.

Let me know if that doesn't make sense :)