A sherbet is basically something to hold a small dish of ice cream, or for the purist, sherbet. You would think an ice cream dish would look like the pink Dogwood sherbet shown below, hmm?The goblet-y looking glass on the left is also a sherbet, this time from Fostoria. It looks like a cocktail glass or a small wine goblet, not a dish you would eat ice cream from. Fostoria referred to this size as a champagne sherbet, to be precise, the tall champagne sherbet. That's because they did not make this pattern in a champagne flute nor in a full saucer shape and this melds the best of a traditional sherbet with a saucer champagne.
The exact stemware name would depend on what the manufacturer called the item. We're stuck with Fostoria's name but there is no reason you have to limit yourself to using this with sherbet or champagne. It's a super size for a cocktail and this looks stunning holding a melon cup or strawberries.
Don't let the book terms box you in. With your imagination there is no limit to how you can enjoy your glass!