> not in common parlance, it is a failure of a word Harsh but not entirely unfair (it is, after all, how language evolves.) Although I'd counter that "isochron

> not in common parlance, it is a failure of a word Harsh but not entirely unfair (it is, after all, how language evolves.) Although I'd counter that "isochron" isn't uncommon in travel-related situations (cf [1]) and "isochronous" is easily understandable by extension. [1] e.g. in the UK parliament, #7927, "the resident population within the Woolwich 20-minute isochron area was about 60,000" https://publications.parliament.uk/pa/cm200607/cmselect/cmcross/235/6051003.htm https://publications.parliament.uk/pa/cm200607/cmselect/cmcr...