1. A state of tranquility or quiet.
  2. Freedom from civil disturbance.
  3. A state of security or order within a community provided for by law or custom.
  4. Freedom from disquieting or oppressive thoughts or emotions.
  5. Harmony in personal relations.
  6. A pact or agreement to end hostilities between those who have been at war or in a state of enmity.

The emotion of Peace is found in the Bladder meridian in the Water element.

Definition from Dictionary by Merriam-Webster.