What does it mean to dream about peace?
Peace in a dream usually reflects a settling or release of tension, and it can be worth noticing what in the dream, or in waking life, allowed the calm.
Four ways to read it
Each reading below comes from a named tradition and a cited source, so you can see where it came from and decide what fits your dream.
Freud
Freud would read a feeling of peace as a wish satisfied and a conflict, for the moment, laid to rest. He held that the dream can grant the mind the ease it cannot find awake. The calm marks a tension released, if only in sleep.
After Freud, The Interpretation of Dreams (Brill trans., 1913), public domain.Jung
Jung would see deep calm as a sign of the self in balance, the warring parts of the psyche briefly reconciled. He valued such moments as glimpses of wholeness rather than mere rest. The feeling can mark a centering, a return to one's ground.
Jungian concept (our summary).Modern
Continuity research ties peaceful dreams to waking well-being and to the easing of stress. Some accounts suggest restful dreaming reflects and supports a settled state of mind. The feeling is worth weighing against what has lately steadied you.
Continuity hypothesis (our summary).Mythological
Myth pictured peace as a goddess bearing the horn of plenty, and set deep calm in the blessed fields beyond ordinary strife. Many traditions saw stillness on the waters as a sign of favour from above. The feeling was treated as a state both earned and bestowed.
Rosmerta Publishing editorial synthesis (after Bulfinch; Brewer).