Participation in extracurricular activities makes you a well-rounded person. Getting involved in different groups and pursuits is not only educational, but also an opportunity to make lifelong friends.
Notice that the first syllable in this noun is part-, as in, “take part.” Participation is the act of participating, or being related to a larger whole. Another word for this is involvement. A person can enjoy participation in a club, a celebration, or even a conversation.