The act or process of bringing things into harmony; in music, the addition of harmonic parts to a melody.
From harmonise (British -ise form of harmonize) + -ation (noun suffix creating abstract nouns of action/process). This British spelling variant reflects standard English morphology where -ise creates -isation forms.
Musical harmonisation is almost an art form—the same melody can sound completely different depending on what chords harmonise it, which is why jazz standards have dozens of versions with wildly different harmonic flavors.
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