Learner's definition of FRIEND
1 : a person who you like and enjoy being with
I'd like you to meet my friend.
She is such a good/close/dear friend (of mine).
We're fast friends. = We're the best of friends.
He's no friend of mine.
He has always been a good friend to me. [=he has always helped or supported me as a good friend should]
She's my best friend. [=my closest friend]
We are childhood friends. [=we have been friends since we were children]
old friends [=people who have been friends for a long time]
She is an old family friend. = She is an old friend of the family. [=she has known and spent time with the family over many years]
We are just friends. [=we are not in a romantic relationship]
He wants to be friends with my younger sister. [=he wants to be my sister's friend]
She is best friends with my younger sister. [=she is my youngest sister's closest friend]
◊ Friend is sometimes used in a humorous or ironic way to refer to someone who is annoying or disliked.
2 : a person who helps or supports someone or something (such as a cause or charity)
She is a friend of the environment. [=she supports environmental causes]
The strikers knew they had a friend in the senator. [=knew that the senator supported them]
Are you friend or foe? [=do you support us or oppose us?]
a friend in need is a friend indeed
— used to say that a friend who will help you when you need help is a true friend
friends in high places
◊ To have friends in high places is to know people with social or political influence or power.
: to become someone's friend — often + with