Webster’s Revised Unabridged Dictionary · 1913
Eupnæa
Eup·næ′a, n. [NL., fr. gr. εὔπνοια easy breathing; εὖ well + πνεῖν to breathe.] (Physiol.) Normal breathing where arterialization of the blood is normal, in distinction from dyspnæa, in which the blood is insufficiently arterialized. Foster.