a medical condition in which a normal body opening or tubular structure is absent or closed, often congenital (e.g., biliary atresia, esophageal atresia).

（医）通常あるはずの器官や管の開口部が先天的に欠如または閉鎖している状態（例：肝外胆管閉鎖、食道閉鎖）