harmonize

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To bring or come into agreement or harmony. See Synonyms at agree.
2. v. Music To provide harmony for (a melody).
3. v. To be in agreement; be harmonious.
4. v. Music To sing or play in harmony.

Century Dictionary and Cyclopedia

1. To be in harmony. In music, to form a concord; agree in sounds or musical effect.
2. To agree in sense or purport.
3. To agree in sentiment or feeling; be at peace one with another. Synonyms To agree, accord, correspond, tally, square, chime, comport.
4. To make harmonious; adjust in fit proportions; cause to agree; show the harmony or agreement of; reconcile contradictions between.
5. To make musically harmonious; combine according to the laws of counterpoint; also, to set accompanying parts to, as an air or melody: as, a harmonized song.
6. Also spelled harmonise.

Wiktionary

1. v. intransitive To be in harmonious agreement.
2. v. intransitive, music To play or sing in harmony.
3. v. transitive To bring things into harmony, or to make things compatible.
4. v. transitive To provide the harmony for a melody.

GNU Webster's 1913

1. v. To agree in action, adaptation, or effect on the mind; to agree in sense or purport.
2. v. To be in peace and friendship, as individuals, families, or public organizations.
3. v. To agree in vocal or musical effect; to form a concord.
4. v. To adjust in fit proportions; to cause to agree; to show the agreement of; to reconcile the apparent contradiction of.
5. v. (Mus.) To accompany with harmony; to provide with parts, as an air, or melody.

WordNet 3.0

1. v. write a harmony for
2. v. go together
3. v. bring into consonance, harmony, or accord while making music or singing
4. v. bring into consonance or accord
5. v. sing or play in harmony
6. v. bring (several things) into consonance or relate harmoniously