Where does “cycle-a-thon” come from?

cycle-a-thon (English) comes from English cycle, from Catalan cicle, from Latin cyclus, from Ancient Greek κύκλος, from Proto-Indo-European kʷékʷlos, from Proto-Indo-European kʷel- — to turn.

Ancestry of “cycle-a-thon”, step by step

cycle-a-thon traces back through two separate lines of ancestry.

via English cycle

StepLanguageWordMeaning
1EnglishcycleAn interval of space or time in which one set of...
2Catalanciclecycle
3Latincyclusa circle; a cycle, recurring period; a branding...
4Ancient Greekκύκλοςcircle, ring; Any circular object, such as a...
5Proto-Indo-Europeankʷékʷloswheel; circle
6Proto-Indo-Europeankʷel-to turn

via English a-thon

StepLanguageWordMeaning
1Englisha-thon
Every word from Proto-Indo-European kʷel-