Origin: Anc Greek
χάλασις /halasis(=relaxation) > χαλάω/halao(=loose)
failure to relax
Achalasia was described in 1672 by Sir Thomas Willis but the tern was coined in 1929 by Hurt and Rake who realized that the disease was caused by a failure of the lower esophageal sphincter (LES) to relax.
Acalasia is a esophageal motility disorder characterized by difficulty swallowing as most common symptom.