1802, colloquial butty (“companion”), also the form of an older dialect term meaning workmate, associated with coal mining. Itself believed derived from 1530 as booty fellow, a partner with whom one shares booty or loot.
buddy (plural buddies)
A friend or casual acquaintance.
They have been buddies since they were in school.
A partner for a particular activity.
An informal and friendly address to a stranger; a friendly placeholder name for a person one does not know.
Hey, buddy, I think you dropped this.