From another dictionary...
sport ( P ) Pronunciation Key (spôrt, sprt)
n.
1. a. Physical activity that is governed by a set of rules or customs and often engaged in competitively.
b. A particular form of this activity.
2. An activity involving physical exertion and skill that is governed by a set of rules or customs and often undertaken competitively.
3. An active pastime; recreation.
4. a. Mockery; jest: He made sport of his own looks.
b. An object of mockery, jest, or play: treated our interests as sport.
c. A joking mood or attitude: She made the remark in sport.
5. a. One known for the manner of one's acceptance of rules, especially of a game, or of a difficult situation: a poor sport.
b. Informal. One who accepts rules or difficult situations well.
c. Informal. A pleasant companion: was a real sport during the trip.
6. Informal.
a. A person who lives a jolly, extravagant life.
b. A gambler at sporting events.
7. Biology. An organism that shows a marked change from the normal type or parent stock, typically as a result of mutation.
8. Maine. See summercater. See Regional Note at summercater.
9. Obsolete. Amorous dalliance; lovemaking.
Giving the wide range of meanings, then yes diving is a sport. Number three is probably closest, but number one also applies, especially if you read some of the discussions on this board.
And even number nine says that Lawman's right.
Marc