I always thought that the “dog” bit here referred to dogfight. But as they say, “a little knowledge is a dangerous thing". So a little bird-dogging revealed that instead of canine reference, dog in underdog is actually a plank of wood. The word supposedly originates from shipbuilding where the planks of wood (called dogs) were sawn for their construction. The senior saws-man stood on top of the plank and he was the overdog. The junior had to go below the planks. And…….. no brownie points for guessing that he was called the "underdog". As simple as that! :)
Source: Wikipedia, Answers.com
June 05, 2008
Underdog - One that is at a disadvantage.