not to be forgotten (adjective) unforgettable: memorable
Sinonime: arrangement, attunement,
blend, blending, chime, chord, chorus,
composition, concentus,
concert, concinnity,
concurrence, consonance, diapason, euphony, harmonics, mellifluousness, melodiousness,
melody, organum, overtone,
piece, polyphony, richness,
symphony, triad,
tune, tunefulness,
unison,
unityAntonime: cacophony,
discord, jangling