pacifier
3.an innocuous or inert medication; given as a pacifier or to the control group in experiments on the efficacy of a drug.
4.The telly is a universal pacifier. It is now standard practice for mother to keep the children quiet by putting them in the living room and turning on the set.
5.It is unavoidable to have misunderstanding and tension with others during work and study. But humor can, as a “pacifier”, inject a light note into the touchy situation to ease these problems quicker than angry words or quarrels.
