Other forms: affiliated; affiliates; affiliating
An affiliate is a subordinate group or organization associated with a larger group or organization. For example, the American broadcasting company NBC has hundreds of affiliate stations around the country.
Affiliate comes from the Medieval Latin term affiliat, meaning "adopted as a son," though it's unlikely NBC sees its affiliate companies in quite that way. The word can also be used to describe someone who simply hangs out with someone else a lot, or keeps company with them regularly, whether for business or not.