The word "dude" is an informal term used primarily in American English to refer to a person, typically a man or boy. It can convey a sense of friendship or camaraderie and is often used to address someone in a casual manner. Over time, "dude" has also become a gender-neutral term, used to refer to people irrespective of their gender.
The word "dude" originated in the late 19th century in the United States. It was initially used to describe a well-dressed man, often in a somewhat sarcastic or mocking way. The exact origin is uncertain, but it is thought to be derived from the word "doodle," which likened a dandy or city fellow to a foolish person.