The following is the July 18, 2023, Congressional Research Service report, Hold on Nominations.
From the report
In the Senate, a hold on a nomination is a communication to the majority or minority leader that a Senator would object to approving the nomination by unanimous consent. When Senators inform their leader that they would object to approving a category of nominations by unanimous consent, such as all nominations to a particular government agency, they are said to be placing a blanket hold
https://news.usni.org/2023/07/18/report-to-congress-on-senate-nomination-holds