triathlon

noun

tri·​ath·​lon trī-ˈath-lən 

-ˌlän,

 nonstandard  -ˈa-thə-

: 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

Ten competed primarily in ultramarathons and several others specialized in Ironmans, multiday triathlons and cycling races. —Jason Dinh, Scientific American, 20 Oct. 2025

What about true super-elites like Kilian Jornet and triathlon star Kristian Blummenfelt? —Alex Hutchinson, Outside, 20 Oct. 2025

Still, her friends convinced her to sign up for a short local triathlon in 2004. —Matthew Futterman, New York Times, 17 Oct. 2025

Several streets around the Sacramento region will be blocked to traffic due to the Ironman California triathlon — with closures in place before, during and after the event. —Veronica Fernandez-Alvarado updated October 16, Sacbee.com, 16 Oct. 2025

Word History

Etymology

tri- + -athlon (as in decathlon)

First Known Use

1924, in the meaning defined above

Kids Definition

triathlon

noun

tri·​ath·​lon ˌtrī-ˈath-ˌlän 

: an athletic contest that is a long-distance race consisting of three phases (as swimming, bicycling, and running)