If a terminology database term was changed before, the History button is available in the header of the Term Section, while viewing the entry where the term belongs. Clicking on this button will display the history of changes in the term.
The current term is listed first followed by its previous term. Each version of the term is listed as a separate Term Section. The headers of the old versions are grey, indicating their History status, and also show their version.
Each Term Section contains a list of attributes and their values for each version of the term, so you can see any changes over time.