- The definition of bub is a slang term for a male friend.
An example of a bub is a teenage boy's name for his best friend.
bub definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
Slang brother; boy; buddy: used in direct address
Origin: ; from German bube, boy
bub definition by American Heritage Dictionary
Used as a term of familiar address, especially for a man or boy: See you around, bub.
Origin: Probably alteration and shortening of brother.