Noun
(usually and especially) Such obstruction in the esophagus: esophageal achalasia.
Coordinate term: pseudoachalasia
(strictly) Such esophageal achalasia of primary (idiopathic) nature: primary esophageal achalasia.
(occasionally) Such obstruction due to impairment of other gastrointestinal tract smooth muscles.
Source: en.wiktionary.org