"on-hold" was a wording used between 2013 and 2019. Nowadays, it's used "closed":
on-hold has no tag wiki and has 15 questions.
closed-questions has 212 questions. The tag excerpt is the following:
Anything about questions that were closed by community or a moderator
I found this tag while searching about Super User community standards related to questions about spreadsheet formulas, more specifically in the following question:
Meta Stack Exchange
- Every "close" has its thorn: replace "close" with "on hold" for the first five days
- Closing changes: [on hold], unclear, too broad, opinion-based, off-topic reasons, bye-bye to Too Localized
Stack Oveflow Blog
- New post notices: Improving feedback on Stack Overflow questions Posted in 2019. It announces the replacement of "on hold" by "closed"