Key Difference: Buddy is an informal way to particularly refer to a male friend. On the other hand, a friend is someone you hang out with in a group, someone to talk to, and to laugh with.

Buddy and friend both are also used as synonyms. Essentially, friendship is a relationship between two people who hold mutual affection for each other. However, we always tend to label our relationships, such as friend, close friend, true friend, best friend, etc. 

According to Dictionary.com, ‘Buddy’ is:

• To be a companion; be friendly or on intimate terms.
• Buddy up,
• To become friendly; be on friendly or intimate terms.
• To work closely together: to buddy up with a student from another high school.
• Buddy up to, to become friendly with or curry the favor of.

Buddy is an informal way to refer to a male friend. It might refer to a best friend, or in the American English, it is also applicable for mate. It also specifically denotes a friend with whom one engages in a particular activity, such as study buddy, etc. It is an informal word, but not slang.

According to Dictionary.com, a ‘friend’ is:

• A person attached to another by feelings of affection or personal regard.
• A person who gives assistance; patron; supporter: friends of the Boston Symphony.
• A person who is on good terms with another; a person who is not hostile: Who goes there? Friend or foe?
• A member of the same nation, party, etc.
• A person associated with another as a contact on a social-networking Website: We've never met, but we're Facebook friends.

A friend is someone you hang out with in a group, someone to talk to, and to laugh with. Friends stand out in a group of people. Friends are someone with whom you are happy to spend time with when you doing absolutely nothing at all, someone who doesn't mind driving you on stupid errands; someone who tries to help you. A friend is someone who would never intentionally hurt you, lie to you, deceive you, manipulate you, abuse you and who takes great care to be kind to you. They are the one who will try to help you, even when they have no idea how. They’ll come with you when you have to do boring things like watch bad recitals, go to stuffy parties, or wait in boring lobbies. Friends are the ones on whom one can always depend on and for whom you will do anything, and they for you. They are the shoulders to cry on, because they are always there for you and they truly know you and care about you.

Comparison between Buddy and Friend:

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