Meaning of achalasia

ach•a•la•sia

Pronunciation: (ak"u-lā'zhu, -zhē-u, -zē-u), [key]
— n. Med.
  1. inability of a circular muscle, esp. of the esophagus or rectum, to relax, resulting in widening of the structure above the muscular constriction.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.