Ôr'thop-næ'a or Or-thŏp'ny

Ôr'thop-næ'a, Or-thŏp'ny, n. [Gr. ὀρθόπνοια, from ὀρθός, straight, right, and πνεῖν, to breathe; Lat. orthopnæa, Sp. & It. ortopnea, Fr. orthopnée.]

1. (Med.) A disease in which respiration can be performed only in an erect posture.
2. Hence, any difficulty of breathing.