peace
Synonym discussion
Sense: noun/1
For noun/1, peace is the broad word for a condition with no war or serious conflict between countries, groups, or people. Harmony is more often used for families, teams, or friendships getting along smoothly, so it sounds less political. Calm usually describes a quiet feeling or atmosphere, which makes it closer to noun/2 than noun/1. Ceasefire is narrower: it means an agreement to stop shooting, often for a limited time, and the wider conflict may still continue. Use peace when you mean the larger stable condition after fighting ends. You can say The village finally had peace after the troops left, but A ceasefire was signed at noon.
Etymology
Peace came into English through Anglo-French from Latin pax. The same Latin family is linked to pacisci, meaning to agree, which also gave English pact. That history helps explain why peace can mean both calm relations and a formal end to fighting.