The phrase "school bell" refers to a ringing sound made by a bell in a school building. It typically indicates the start or end of classes, or a change in activity.
Sentences with «school bell»
Listen carefully and you won't hear the ubiquitous sounds of school bells ringing. (edutopia.org)
Learning doesn't stop when the last school bell rings. (foundationsinc.org)
The parade of sales - tax holidays continued until just a few weeks before school bells ring. (creditcards.com)