1. the quality of harmony between elements, for example, in music.

2. in communication, harmony between content (denotative meaning) and intent (connotative meaning); for example, if a talk on the subject of peace is uttered in peaceful tones, content and intent agree and the communication is said to possess consonance.

3. in social psychology, the extent to which the components of an attitude are internally consistent or in agreement with each other. See cognitive consonance.