From Longman Dictionary of Contemporary Englishtriathlontri‧ath‧lon /traɪˈæθlən/ noun [countable] DSOa sports competition in which competitors run, swim, and cycle long distances
Examples from the Corpus
triathlon• He did the swim in the San Diego Challenge, a triathlon that awarded two spots for the Ironman.• He was speeding through the big loop on his bike; he was in training for a triathlon.• My current mileage is only 10-20 miles per week, but I would like to move up to longer distances and triathlons.• Once he realized his own exceptional stamina, he advanced to marathons and triathlons, then ultra-marathon cycling races.• He plans to win his age group of the Ironman triathlon in Hawaii when he is 70.• Okay, you're a participant in iron man triathlons?• No worries about sharks spotted in Sydney Harbor for the triathlon.• Now they're tuned up and ready to take the plunge for the triathlon season ahead.Origin triathlon (1900-2000) tri- + Greek athlon “competition” 