Things that are the same in essence are often called differently. In some processes it is convenient to call primary requirements a "Request", in others a "User story", and in others a "Backlog item", although in essence they are the same thing. Retraining to use a new term is uncomfortable, and in ALM it is unnecessary. You can rename any term, providing a convenient language of communication inside the team.
The term list shows the original (system) term on the left and its current (project) value on the right. You can change the text in the right-hand part of the list; the value you enter is saved automatically.
To filter terms conveniently, use the "Term" filter: enter text in this field and press Enter, after which all system terms are filtered by that substring. If necessary, you can delete all custom term values by selecting the corresponding item in the "Actions" menu.