Most likely you are, basically everything in SharePoint is based on a Content Type, base one being the Item. Go for list/library settings, and in Advanced settings, choose Yes to "Allow management of Content types". As soon as you Save you should see the list of Content types added to your list.
They are basically the blueprint definition of your list/library. Once, done, click on the Name of the CT and you shall see another Page, having PARENT most likely the Exact same name - is confusing, because actually the CT on your list is an Instance of that one (its child).
Click again on the Parent and you shall be able to see the COLUMN you do not need. Here you have 2 choices:
- Mark it Hidden - which shall translate into this being hidden from
User Interface, but still be part of the CT definition -just in
case someone else is actually using that.
- Delete it completely -at it shall disapear from UI, discard completely all data and remove it from any place where it is used (!!!!)