orthopny

{ ‖ } n. [ L. orthopnoea, Gr. &unr_;; '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. [ 1913 Webster ]