1. A substance which relieves irritation by forming a protective film on the mucous membranes in the mouth: In medicine, a demulcent is a soothing preparation; especially, one that is applied to decrease the intensity of an irritation of an inflamed surface.
2. Etymology: from Latin demulcent, "stroking caressingly or lovingly" from the verb demulcere, from de-, "down, away" + mulcere, "to soothe, to pet", or "to soften".