In the context of relationships, which word indicates harmony?

The word "peace" is associated with harmony in relationships as it signifies a state of tranquility and absence of conflict. In harmonious relationships, individuals communicate openly and respectfully, listen to one another, and collaborate effectively, leading to mutual understanding and a sense of calm. Peace embodies the idea of a positive, cooperative atmosphere where disagreements are resolved amicably, and individuals feel safe and supported.

The other words in the question evoke negative connotations related to relationships. Disagreement suggests a difference in opinions that can lead to tension. Conflict refers to a state of discord or argument, indicating a breakdown in communication. Strain implies stress or pressure in a relationship, often arising from unresolved issues or external factors. Thus, "peace" is the clear choice that conveys an overarching sense of harmony and stability in relationships.