What is the definition or description of: continuous positive airway pressure?

CPAP. Continuous positive airway pressure involves the constant application of external pressure to all phases of breathing. The patient would feel as if breathing against the constant headwind. Inhalation would be easier as the pressure enables air entry. Exhalation prevents complete relaxation. This can be helpful in obstructive sleep apnea or pulmonary disease.
Definition. Exactly what the term states: Continuous positive airway pressure in an airway that cannot stay open for breathing otherwise. Must commonly used for obstructive sleep apnea.