verb
quell
KWEL/kwel/
To bring something troubling or disruptive under control.
She uses an extinguisher to quell the small fire.

Etymology
The original meaning was literally to kill. This softened into causing something to cease, allowing the verb to describe suppressing unrest or calming fear.
In context
its aim was on the one hand to quell the violence on the frontier and it was also aimed to stop the influx of settlement over the appalachian mountains
More examples
- Firefighters worked to quell the blaze.
- She raised a hand to quell the argument.
- The authorities tried to quell the unrest.
Forms
quell · quells · quelled · quelling