It's more of a porch topic I suppose, because over the years (decades...) we've had numerous discussions about what a "sport" really is.
And over the years (decades...) some of you have disagreed with me, but I have two simple criteria I use to determine what a "sport" is.
1) The outcome cannot be judged, it must have a clear, objectively determined winner and loser.  So gymnastics is not a sport.  Figure skating is not a sport.  And as Slick observed, non-KO boxing is not a sport.  They are certainly "athletic competitions" but they are not sports. 
2) It requires being an athlete to play the sport.  I don't consider poker, darts, billiards, or bowling to be sports, nor do I consider golf to be a sport.  They are all competitions requiring very specific skills-- which in some cases many consider to be highly prized skills like golf-- but it's not a sport.