Where does “デカスロン” come from?

デカスロン (Japanese) comes from English decathlon, from English -athlon, from Ancient Greek ἆθλον, from Proto-Indo-European h₂weh₁- — to blow.

Ancestry of “デカスロン”, step by step

StepLanguageWordMeaning
1EnglishdecathlonAn athletic contest consisting of ten events...
2English-athlonContest
3Ancient Greekἆθλονprize of a contest; contest; place of combat,...
4Proto-Indo-Europeanh₂weh₁-to blow
Every word from Proto-Indo-European h₂weh₁- →Every word from Ancient Greek ἆθλον →Every word from English -athlon →