Knell (noun)

1. The sound made by a bell when it is rung slowly and mournfully, often associated with death or funerals.
2. A symbol or sound that signifies the end of something or the arrival of a significant event, especially a sad or unfortunate one.

Origin:

The word 'knell' comes from the middle english word knellen, which means 'to ring a bell,' especially in a slow, mournful way. it is thought to have originated in the 15th century.

Examples:

1. The knell of the church bell marked the end of the funeral ceremony.
2. The knell of the sinking ship's bell was a chilling sound, signaling the imminent doom of the crew.
3. The knell of the grandfather clock announced the arrival of midnight, signaling the end of the old year and the start of a new one.
4. The knell of the school bell signaled the end of the school day and the start of summer vacation.
5. The knell of the alarm clock signaled the start of another day, reminding the tired man to get up and face the challenges ahead.