A furlong is 1/8 of a mile. It is used in horse racing, and by announcers
in the sport ("...at the furlong, it's SloMo, followed by Silky
Sullivan...."). Very traditional, and very much a niche thing. Sports
writers once used to use it also to describe the old 220 yard track events,
which fortunately have been eclipsed by the 200 m distance, which is almost
the same. I am happy to say that even old-fashioned track coaches and fans
almost always refer to this event in 200 m terms and never mention 220 yards.
In California high school track there used to be a 1320 yard and 660 yard
run, both of which no longer exist. These were multiples of the "furlong",
being three and 1 1/2 laps of the old 440 yard tracks, respectively. They
were run by younger boys, in the days before girls ran track, the concept
being that they were too frail to run 880 yards and a full mile. I
remember because I used to run them as a high school sophomore!
HARRY WYETH