Look up snifter in Wiktionary, the free dictionary.
A snifter glass.
A snifter (also called brandy snifter, cognac glass, or balloon) is a type of stemware, a short-stemmed glass whose vessel has a wide bottom and a relatively narrow top. It is mostly used to serve aged brown spirits such as brandy and whisky.
The large surface area of the contained liquid helps evaporate it, the narrow top traps the aroma inside the glass, while the rounded bottom allows the glass to be cupped in the hand, thus warming the liquor. Most snifters will hold between 180–240 ml (6–8 oz.), but are almost always filled to only a small part of their capacity. Most snifters are designed so that when placed sideways on a level surface, they will hold just the proper amount before spilling.