harmonization

Concise Oxford English Dictionary © 2008 Oxford University Press:
harmonize /ˈhɑːmənʌɪz/ (or harmonise)

▶verb

• 1 provide harmony for.

  ■ sing or play in harmony.

• 2 make or be harmonious or in agreement.

  ■ make consistent: plans to harmonize the railways of Europe.

– derivatives
harmonization noun,
harmonizer noun.