With capital initial, Friend denotes a member of the Religious Society of Friends, a Quaker; the name is recorded from the late 17th century.
a friend at court a person in a position to use their influence on one's behalf. The term is recorded from the medieval period, and in early uses refers to a sovereign's court rather than a tribunal.
a friend in need is a friend indeed proverbial saying, mid 11th century; a friend in need is one who helps when one is in need or difficulty. The same idea is found in the 5th century bc in Greek, in the Hecuba of Euripides, ‘for in adversity good friends are most clearly seen.’ The Roman writer Ennius (239–169bc) has, ‘a sure friend is known in unsure times.’
friend of Dorothy a term for a gay man for whom Dorothy in the Wizard of Oz (1939), as portrayed by Judy Garland, is an icon.
See also the enemy of my enemy is my friend, fair-weather friend, friends, lend your money and lose your friend.