Sherbet is a sweetened frozen dessert made with fruit and some sort of dairy product such as milk or cream. Egg whites are also sometimes used in making sherbet.
Sherbet can be made with fruit juice or puréed fruit or both. The amount of dairy product in sherbet is low compared with other frozen desserts. Whereas ice cream will contain at least 10 percent butterfat (often as high as 20 percent), and gelato between four and eight percent, sherbet contains only 1 to 2 percent butterfat.
Common sherbet flavors include orange, raspberry, lemon and lime. There's also a thing called rainbow sherbet (pictured here), which is made by combining layers of raspberry, lime and orange sherbet.
The word "sherbet" is often mispronounced and misspelled as "sherbert," as if it rhymes with Herbert. Which it doesn't. It's pronounced the way you would say "sure, but..."
Having said that, wouldn't someone named Herbert Sherbert make a great children's book character?
(I know what you're thinking : "Sure, but...")
In any case, sherbet is not to be confused with sorbet (even though the words are slightly similar). Sorbet is made of frozen fruit juice, without or without pureed fruit, along with some sort of sweetener, but no milk, cream or other dairy.
If you were making orange sherbet, you'd use orange juice, combining the juice, sugar and milk in an ice-cream maker and processing until done. Orange zest, lemon juice and vanilla extract would also be nice.
In other cases, you'd use a fruit purée rather than juice. To make raspberry sherbet, puree frozen raspberries, then strain to remove the seeds. Then combine the purée, milk, sugar and lemon juice and process in your ice cream maker.
You could use whole milk or 2% milk. For a creamier sherbet, you could add a splash of cream.
By the way, you can make sherbet in the Vitamix, if you have one of those. I got one a few years ago, and it's terrific. One of the things I love to use it for is making peach sherbet in the summertime. Start with about a pound of frozen sliced peaches (soften them at room temperature for 20 minutes or so), a cup of milk, about 1/4 cup of honey, and maybe 1/2 tsp of vanilla extract. Purée in the Vitamix for 30–60 seconds and serve.
I like to use honey because it's liquid, but you can use granulated sugar, too — about 6 Tbsp of sugar is the equivalent of 1/4 cup of honey.