General terms:
* Toll: This is a common word for a slow, solemn sound of a bell, often used for funerals or other mournful occasions.
* Peal: This refers to a series of bell sounds, typically played in a specific pattern. It can be long or short depending on the arrangement.
* Boom: This is a simple, descriptive term for a loud, resonant sound, which can be used to describe a long sound of a bell.
More specific terms:
* Bellringing: This refers to the art of ringing church bells in a specific pattern, often used to signal events or for artistic expression.
* Chime: This can refer to a series of bells sounding together, often in a musical sequence.
* Carillon: This is a specific type of musical instrument that consists of a set of bells played by a keyboard.
Other possibilities:
* Prolonged ringing
* Extended bell sound
* Sustained chime
Ultimately, the best term depends on the specific situation and what you want to emphasize.