Orthopnea

Part of speech: noun

Definitions

1. A condition where a person has trouble breathing while lying down flat on their back
2. Experiencing shortness of breath that worsens in a horizontal position, making it easier to breathe when sitting or standing
3. Difficulty in respiration caused by lying flat, which improves upon sitting upright or standing

Etymology: "Orthopnea" is built from two Greek elements. "Ortho-" comes from Greek "orthos," meaning "straight" or "upright," and "-pnea" comes from Greek "pnoia," meaning "breathing," from "pnein," "to breathe." Put together, the name describes breathing that is best managed in an upright position. The compound is a technical coinage from classical Greek roots rather than a word the ancients used. Its meaning is precise: a patient who lies flat finds breathing harder, and sitting or standing up relieves the difficulty. The "ortho-" prefix is the same one found in words like "orthodontics" and "orthopedic," where it signals straightness or correction.