When logged into Magento 2 as the admin, the following steps are:
1. Click on 'Catalog' and then click on 'Categories'.
2. Click on 'All Store Views' (which is found next to 'Scope') to select the desired store view or language.
3. Select the category you wish to rename (from the list on the left side) and then change the name within the 'Category Name' section.
4. Click on 'Save' and you're done!