Sorbet is sort of like ice cream’s healthier cousin. It’s a sweet frozen dessert, but it is not ice cream or Sherbert. At least, not in the U.S. In America, sorbet is an icy, fruit-flavored dessert that does not contain any dairy. The fact that is does not contain dairy is what distinguishes it from ice cream and Sherbert.
However, you could say that it is similar to Italian ice. Sorbet typically contains water, fruit and/or fruit juice, and sometimes an additional sweeter. Most sorbets are vegan, with the rare exception of those that contain honey.
Sometimes the words sorbet and Sherbert are used interchangeably, but they are never the same thing. If a sorbet in the U.S. is actually a Sherbet, then it is a Sherbert, period. A Sherbert, by definition, is a sorbet that contains 1% to 2% butterfat or milkfat. Anything that contains 10% or more is considered ice cream.
In other parts of the world, the terms sorbet and Sherbert might mean the same thing or might refer to some different altogether. For example, in Britain, sorbet is a fizzy powder used to make sugary drinks. It’s not even a frozen dessert. So if you’re traveling abroad, or you are from abroad, you should keep this in mind.