The natural progression of language by means of:
1.) Abbreviation (bro from
brother)
2.) Word reversal (cool and hot for good)
3.) A need for secrecy (dime bag for $10 of pot or 1/10oz of
weed)
4.) Degree of separation (green for
marijuana)
5.) Expressed honorific (calling a close friend your brother)
6.) Combination (Branjalina for Brad Pit and Angelina Jolie)
7.) Any other word not recognized by the major dictionaries as viable, but which a large portion of the population will understand the meaning of.
Though he did not allow slang to be used in his classroom, Prof. Smith was known to call his students "dude", "man", and "bro"
outside of
class in a feeble attempt to regain some of his lost
youth.