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Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: An esophageal condition involving the same obstructive character as achalasia but not of a primary (idiopathic) nature (cause); it is called pseudoachalasia when the term achalasia is intended to mean only the type of such obstruction that is of primary nature, whereas in other terminological schemas it is classified as a type of achalasia, called secondary achalasia in coordinate rank with primary achalasia (true achalasia). Full definition →
Etymology from Wiktionary, CC BY-SA 4.0.