ILL GIVE U BRAINLYIST

Answer:
It is a competition that has three parts.
Explanation:
Definition of triathlon : an athletic contest that is a long-distance race consisting of three phases (such as swimming, bicycling, and running) Examples of triathlon in a Sentence Recent Examples on the Web Katelynn Stearns, 33, is a summer triathlete who was ecstatic and exhausted after her winter triathlon debut.