What does soporific mean?
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From our dictionary:sop•o•rif•ic
Pronunciation: (sop"u-rif'ik, sO"pu-), [key]
—adj.
1. causing or tending to cause sleep.
2. pertaining to or characterized by sleep or sleepiness; sleepy; drowsy.
—n.
something that causes sleep, as a medicine or drug.