When I think of peace, I always think of equanimity, abiding in peace and clarity even amidst a storm. It's kinda like the calm eye of the storm. I believe a Buddhist definition that's given is not to be pulled by our attachments and also not to be pushed by our aversions. That means our attachments and aversions don't control us. I like that idea a lot and with Dharma practice, I can see how situations can arise that will make it the perfect occasion to practice.
Anyway, I found a very nice article that goes along with the definition of equanimity:-
The English word equanimity refers to a state of being calm and balanced, especially in the midst of difficulty. In Buddhism, equanimity (in Pali, upekkha; in Sanskrit, upeksha) is one of the Four Immeasurables or four great virtues (with compassion, loving kindness, and sympathetic joy) that the Buddha taught his disciples to cultivate.
But is being calm and balanced all there is to equanimity? And how does one develop equanimity?
Definitions of Upekkha
Although translated as "equanity," the precise meaning of upekkha seems hard to pin down. According to Gil Fronsdal, who teaches at the Insight Meditation Center in Redwood City, California, the word upekkha literally means "to look over." However, a Pali/Sanskrit glossary I consulted says it means "not taking notice; disregard."
According to Theravadin monk and scholar Bhikkhu Bodhi, the word upekkha in the past has been mistranslated as "indifference," which has caused many in the West to believe, mistakenly, that Buddhists are supposed to be detached and unconcerned with other beings . What it really means is to not be ruled by passions, desires, likes and dislikes. The Bhikkhu continues,
"It is evenness of mind, unshakeable freedom of mind, a state of inner equipoise that cannot be upset by gain and loss, honor and dishonor, praise and blame, pleasure and pain. Upekkha is freedom from all points of self-reference; it is indifference only to the demands of the ego-self with its craving for pleasure and position, not to the well-being of one's fellow human beings."
Gil Fronsdal says the Buddha described upekkha as "abundant, exalted, immeasurable, without hostility and without ill-will." Not the same thing as "indifference," is it?
Thich Nhat Hanh says (in The Heart of the Buddha's Teaching, p. 161) that the Sanskrit word upeksha means "equanimity, nonattachment, nondiscrimination, even-mindedness, or letting go. Upa means 'over,' and iksh means 'to look.' You climb the mountain to be able to look over the whole situation, not bound by one side or the other."
We also can look to the life of the Buddha for guidance. After his enlightenment, he did not live in a state of indifference. Instead, he spent 45 years actively teaching the dharma to others.