Orthopnœa

{ ‖Or′thop‐nœ″a (?), Or‐thop″ny (?), } n. [L. orthopnoea, Gr. �; ορθὄσstraight, right + πνει̑ν to breathe: cf. F. orthopnée.] (Med.) Specifically, a morbid condition in which respiration can be performed only in an erect posture; by extension, any difficulty of breathing.