Term store reports
You can access reports for Term store in the SharePoint admin center. This feature requires a Microsoft Syntex license.
Expand Reports, and then select Content services.
The following reports are available: term store operations, term store composition, open and closed term sets, and terms without synonyms.
Term store operations
View the top operations that have taken place in your term store in a 15-day period and see a trend of daily volumes in that period. This information is useful when you want to understand the nature of changes in your term store at a high level and identify any unexpected trends in volumes of operations.
Term store composition
View the distribution of types of terms between regular managed terms and enterprise keywords. Move multiple keywords to managed terms if desired. This information is useful when you want to identify if your users are actively using keywords. You can review them to identify potential candidates for managed terms.
Open and closed term sets
View the distribution of open and closed term sets. This is useful if you want to understand how many term sets allow users to add terms. You can convert them to closed if desired, for example if the volumes are growing unexpectedly.
Terms without synonyms
View the number of terms in each of the added working languages that don't have synonyms defined. This information is useful to help identify languages where you want to define synonyms. Synonyms help end users disambiguate and find the correct terms to tag their content.