マラソン選手[走者].
a marathon called the Boston marathon
A twenty-mile Marathon.
ベルリンマラソン
I'm worried whether I can run a marathon.
a long distance race of 42.195 kilometres, called a marathon
I was surprised by the popularity of marathons.
I thought about challenging myself to a marathon.
I have run a marathon 3 times before.
Lots of people took part in the marathon.
someone who participates in long-distance races (especially in marathons)