What's milk nog

It can be anything from fruit juice to scalded milk. Egg Nog isn't necessarily an alcoholic beverage though it can be. Typically it is made by mixing eggs with sugar and milk or cream, rum or brandy is added for alcoholic variants. Orange Juice, Apple cider, or wine among other things can be substituted for the milk. It can also be made hot or cold, and served hot or cold.

One such nog is as follows:

Egg and Wine:

beat 1 egg yolk with 1 1/2 tsp sugar syrup, until creamy. Add 1 oz. sherry and stir well. beat an egg white until stiff, fold into drink and sprinkle with nutmeg.

{from "Complete World Bartender Guide", 1993.}