Besides the TBX fields, you can also configure your own custom fields in your terminology management tool.
Go to Settings and search for Terminology Management
Click on Configure to access the Customization page of Terminology management and TBX
Go to Access rights > Custom field and click on Configure custom fields
Customization screen opens. Select Resources to define additional input fields for your translation memories and terminology databases. You can create up to 20 custom fields per category.
Use Add to create a new custom field.