It can be used as an adjective or a noun:
As an adjective:
* Un jeune homme: a young man
* Une jeune fille: a young girl
* Un jeune chien: a young dog
As a noun:
* Les jeunes: the young people
* La jeunesse: youth (abstract concept)
It's important to note that "jeune" can also be used as a noun to describe something new, especially in the context of wine or cheese:
* Un vin jeune: a young wine
* Un fromage jeune: a young cheese
Let me know if you have any other questions about the word "jeune" or any other French words!