Peace is the restful and content state of our soul.
There is an innate restlessness to human nature. Even at quiet times we can sense it’s presence in the background. Restlessness is a close cousin of dissatisfaction and both are usually present at the same time.
Peace is the absence of restlessness and dissatisfaction and we feel its presence infuse our soul
Peace is closely associated with stillness & contentment, but can even be felt in a noisy crowd. When we are at peace we feel serene.
In his book ‘a million Thoughts’, Om Swami identifies Happiness & Freedom as the two innate drivers of human behaviour. I added a third, Peace.