Webster's Revised Unabridged Dictionary · 1913

Eupnaa

Eupnaa , noun

[New Latin, from gr. {not transcribed} easy breathing; e'y^ well + {not transcribed} to breathe.]

(Physiology) Normal breathing where arterialization of the blood is normal, in distinction from dyspnaa, in which the blood is insufficiently arterialized. — Foster

Also: Eupnaea