予鈴
1
bell signalling that work, class, etc. will formally begin shortly;first bell;warning bell
See also:
本鈴 (ほんれい)
予鈴だ。校門の辺りにいた生徒たちが一斉に足を速める。
It's the class bell. The pupils that had been around the school gate quickened their steps as one.