1 a : a state in which there is no war or fighting [noncount] ▪ After many years of war, people on both sides were longing for peace. ▪ We said a prayer for world peace. ▪ They have lived in peace [=peacefully] for many years. ▪ We grew up in a time when the nation was prosperous and at peace. [=not fighting a war] ▪ The United Nations has sent troops to the area to try to keep (the) peace. [singular] ▪ a lasting peace ▪ The two countries have maintained an uneasy peace. [=a state in which fighting could start at any time] b [singular] : an agreement to end a war ▪ He tried to negotiate a peace between the warring countries. ▪ After many years of war, the two countries have finally made peace (with each other). —often used before another noun ▪ a peace agreement/accord/treaty ▪ a peace initiative/conference ▪ peace talks ▪ the peace process [=the steps that are taken by countries or groups that are trying to end a war] c [singular] : a period of time when there is no war or fighting ▪ There was a peace of 50 years before war broke out again.
2 [noncount] a : a quiet and calm state ▪ I just want a few moments of peace. = I just want a little peace and quiet. ▪ Why won't they leave him in peace? [=why won't they stop bothering him?] b : a safe and calm state in a public place ▪ Peace and order were finally restored in the town. ▪ He was arrested for a breach of the peace. = He was arrested for disturbing the peace. [=for behaving in a loud or violent way in a public place] —see also justice of the peace
3 : a state in which a person is not bothered by thoughts or feelings of doubt, guilt, worry, etc. [singular] ▪ After years of therapy, he has finally achieved an inner peace. [noncount] ▪ He is searching for inner peace. ▪ She has found peace (within herself). ▪ Insurance can provide you with peace of mind. ▪ The problem was settled and his mind was at peace. ▪ They are at peace with each other. ▪ She's at peace with their decision. [=she has accepted their decision] ▪ May our dearly departed friend rest in peace. [=we hope our friend who has died will have peace after death]
4 [noncount] : a state in which people do not argue or cause trouble ▪ There will never be peace between those families. ▪ She wants to go, and we won't have any peace until we agree to let her do what she wants.