Noun:
1: friend a person you know well and regard with affection and trust; "he was my best friend at the university"
2: ally, friend an associate who provides assistance; "he's a good ally in fight"; "they were friends of the workers"
3: acquaintance, friend a person with whom you are acquainted; "I have trouble remembering the names of all my acquaintances"; "we are friends of the family"
4: champion, booster, protagonist, admirer, friend, supporter a person who backs a politician or a team etc.; "all their supporters came out for the game"; "they are friends of the library"
5: quaker, friend a member of the Religious Society of Friends founded by George Fox (the Friends have never called themselves Quakers)