orthopnoea/ɔrˈθɒpniə/EtymologyFrom ortho- + -pnoea, from Ancient Greek ὀρθόπνοια (orthópnoia, “breathing only in an upright posture”), from ὀρθός (orthós, “straight”) + πνοή (pnoḗ, “breath”).orthopnoea means shortness of breath when lying flat, causing the person to have to sleep propped up in bed or sitting in a chair. Lexicurio rates it Sui generis — a strength score of 91 out of 100.orthopnoea is pronounced /ɔrˈθɒpniə/.nounShortness of breath when lying flat, causing the person to have to sleep propped up in bed or sitting in a chair.