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

In many cases, these mysterious objects turn out to be early hygiene devices that were common in the early 20th century but have since fallen out of use. One likely candidate is a wall-mounted soap holder or soap dish with a built-in drain. Unlike modern dispensers, these were designed to hold solid bars of soap and often included ridges or holes to allow water to drain away, preventing the soap from dissolving too quickly.

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.