Discovered this in a very old school washroom 1920’s. What is this thing?

Another possibility is that the object is an antique toothbrush holder or rinsing cup holder. During that era, public hygiene practices were evolving, and schools sometimes installed shared fixtures intended to promote cleanliness among students. These holders were often mounted near sinks and could include multiple slots or rings for holding cups or brushes.

In some older washrooms, you might also find what appears to be a ceramic spout or small basin attached to the wall, which could have been part of an early drinking fountain or a rinse station. These were designed for quick use and were typically placed at a height convenient for children.