Dictionary
be'ta block"er
Pharm.
any of various substances that interfere with the action of the beta receptors: used primarily to reduce the heart rate or force in the prevention, management, or treatment of angina, hypertension, or arrythmias.
Also,be'ta-block"er.Cf.
alpha blocker. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.