Should a comparative or a superlative be used in this sentence? Why? In my experience, it's better / it's best to have only one best friend who is reliable.
The base meaning of "they are the best of friends" is more something like "of all the friendships you might encounter in the world, theirs counts among the truest/closest". In other words, here "of friends" means "of all the various friendship relationships". So, it's just saying the people in question are very good friends, but it's a distinctive phrase that's often used to emphasize that ...
The meaning of FRIEND is one attached to another by affection or esteem —sometimes used ironically or humorously to refer to a person who is disliked or annoying.
FRIEND definition: 1. a person who you know well and who you like a lot, but who is usually not a member of your…. Learn more.
FRIEND definition: a person attached to another by feelings of affection or personal regard. See examples of friend used in a sentence.
Definition of friend noun in Oxford Advanced American Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.
Your friends are people you know well and like spending time with. You can refer to a friend who you know very well as a good friend or a close friend. He's a good friend of mine. A close friend told me about it. If someone has been your friend for a long time, you can refer to them as an old friend. He or she is not necessarily an old person.
Be friends with, to be on intimate or friendly relations with; Have a friend at court, to have a friend in a position where his influence is likely to prove useful; Society of Friends, the designation proper of a sect of Christians better known as Quakers.