marathon

English marathon comes from French marathon, coined in 1894 by linguist Michel Bréal for the first modern Olympic Games, after Marathṓn, a town northeast of Athens. Phidippides famously ran from Marathon to Athens to deliver news of the Battle of Marathon, and the modern race is based on roughly that distance.

The town's own name traces back to Ancient Greek márathon, meaning 'fennel,' referring to the plant that grew abundantly there — so the word moved from a plant, to a place, to a runner's legendary journey, to the modern race.

The facts don't support a documented English cognate beyond the word itself and its French intermediary form.