Friendship is the state of being friends with someone. A good job, good health, and romantic love are important, but without real friendship, your life might not feel full.
When we talk about friendship, we're often talking about the value of having friends, not just the fact of it. A book might explore the importance of friendship in a young girl's life. You might decide to stop working such long hours and spend more time developing your friendships, in an effort to lead a happier life. A deep friendship can last through many shifts and changes in life, as long as you write or call every now and then.