harmonize
Definitions
To add notes to a melody to produce chords.
To be in or bring into agreement or consistency.
To form a pleasing or consistent whole.
Examples
The choir practiced for hours to ensure their voices would harmonize perfectly during the performance.
We need to harmonize our schedules so that we can attend the conference together.
Synonyms
coordinate integrate balance accord synchronize reconcile unify
Antonyms
clash conflict disagree dissonate mismatch contradict discord