v. i.

  1. To agree in action, adaptation, or effect on the mind; to agree in sense or purport; as, the parts of a mechanism harmonize.
  2. To be in peace and friendship, as individuals, families, or public organizations.
  3. To agree in vocal or musical effect; to form a concord; as, the tones harmonize perfectly.

v. t.

  1. To adjust in fit proportions; to cause to agree; to show the agreement of; to reconcile the apparent contradiction of.
  2. To accompany with harmony; to provide with parts, as an air, or melody.