consonant

Consonance is the quality of stability and restfulness that certain note combinations produce. Perfect consonances — the unison, octave, and perfect fifth — are the most stable intervals in Western music. Imperfect consonances — major and minor thirds and sixths — add warmth and colour while still sounding resolved. What counts as consonant has changed dramatically over the centuries. Medieval musicians considered only octaves and fifths consonant. Renaissance composers embraced thirds and sixths. Jazz musicians treat complex chords with sevenths, ninths, and elevenths as stable. The boundary between consonance and dissonance is partly acoustic and partly cultural — shaped by what our ears have been trained to accept.