{ ||Or`thop*nœ"a (?), Or*thop"ny (?), } n. [L. orthopnoea, Gr. &?;; 'orqo`sstraight, right + pnei^n 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.