* Joindre: This is the most general word for "join" and can be used in many situations. For example, "Joindre les deux morceaux" means "join the two pieces."
* Rejoindre: This word means "to rejoin" or "to meet up with." For example, "Rejoindre ses amis" means "to meet up with his friends."
* S'unir: This word means "to unite" or "to come together." For example, "S'unir pour la paix" means "to unite for peace."
You can also use the verb "être" with a preposition to express joining. For example, "être avec" means "to be with," and "être parmi" means "to be among."
It's important to choose the right word based on the specific situation and meaning you want to convey.