What does un mean in french?

"Un" in French means "a" or "one". It's a definite article used before masculine singular nouns.

Here are some examples:

* Un livre: A book

* Un chien: A dog

* Un jour: One day

It's important to note that "un" is only used before masculine singular nouns. For feminine singular nouns, you would use "une" (pronounced "oon").

Let me know if you have any other questions about French grammar!