harelip, congenital abnormality in which there is a cleft or split in the upper lip. There may be a single opening in the middle portion of the lip or an opening on each side. The condition frequently occurs along with a cleft palate, an opening in the roof of the mouth. Harelip is usually corrected by plastic surgery soon after birth.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.