Examples of Partitive Articles
Ok, so now that you know the forms, how do you use them, and what do they mean? Here are a few examples of partitive articles in action:
Je mange du gâteau. (I'm eating [some] cake.)
Tu bois de l'eau? (Are you drinking [some] water?)
Il prépare du café pour nous. (He's making [some] coffee for us.)
As you can see, the usual translation of the partitive article is the word "some" in English. You will also see the word "any" used, and as you can see from the translations of the examples, sometimes we simply don't have a word in English and simply say "He's making coffee for us."
The idea behind the partitive article is that it is, again, "part" of the whole thing. It's not "one" thing, like an indefinite article un or une, and it's not "the" whole or "the" specific thing, like a definite article le, la, or les, but rather part, some, or any of the thing. Going back to the coffee example, in English, we understand the sentence to mean that he is making some coffee, even though it is not specified. He is not making all the coffee in the world, and he is not making one single coffee (or even several cups, that being a specific amount), but rather some unspecified amount of coffee. In French, you must have the article before the noun, and because we cannot use a definite or an indefinite article, you use the partitive article.