n. (Eccl. Hist.) A follower of Eutyches [ 5th century ], who held that the divine and the human in the person of Christ were blended together as to constitute but one nature; a monophysite; -- opposed to Nestorian. [ 1913 Webster ]

n. (Eccl. Hist.) The doctrine of Eutyches and his followers. [ 1913 Webster ]

a. [ From Eustachi, a learned Italian physician who died in Rome, 1574. ] (Anat.) (a) Discovered by Eustachius. (b) Pertaining to the Eustachian tube; as, Eustachian catheter. [ 1913 Webster ]

Eustachian catheter, a tubular instrument to be introduced into the Eustachian tube so as to allow of inflation of the middle ear through the nose or mouth. --
Eustrachian tube (Anat.), a passage from the tympanum of the ear to the pharynx. See Ear. --
Eustachian valve (Anat.), a crescent-shaped fold of the lining membrane of the heart at the entrance of the vena cava inferior. It directs the blood towards the left auricle in the fetus, but is rudimentary and functionless in the adult. [ 1913 Webster ]