Peace is generally defined as a state of quiet or tranquillity, as an
absence of disturbance or agitation (Latin derivation Pax = Absentia Belli).
More specifically, it can refer to an absence of violence or war. In this
sense, peace between and within national states is a goal of many persons
and organisations, notably the United Nations. Peace can be voluntary, where
potential agitators choose to abstain from disturbance, or it can be
enforced, by suppressing those who might otherwise cause such disturbance.
Rev. Martin Luther King, Jr. wrote in his Letter from Birmingham Jail that,
"True peace is not merely the absence of tension: it is the presence of justice."