affinity

Affinity in terms of sociology, refers to "kinship of spirit", interest and other interpersonal commonalities. Affinity is characterized by high levels of intimacy and sharing, usually in close groups, also known as affinity groups. It differs from affinity in law and Catholic canon law which generally refer to the marriage relationship. Social affinity is generally thought of as "marriage" to ideas, ideals and causes shared by a tight community of people.