[75w]

Doesn't the word hackney (for a horse) come from the place Hackney (for a hipster)?

so it would be Hackney -> Hack -> Hackney -> Hack

[tuatoru]

The Hackney Horse breed was developed in the 14th century in Norfolk when the King of England required powerful but attractive horses with an excellent trot, to be used for general purpose riding horses.

May well have been named after the district.

1. https://en.wikipedia.org/wiki/Hackney_horse

[ggm]

This is like Proust, and the obsessive deriver-of-original-names character. I'd say its convergent distinct stories, lost in time. Hackney in London refers to a the river bend on the Lea, and an island or peninsula in the river, then the region, Hackney Carriages stem from the horse, the horse's name has now informed french breeds.. its all connected. But, Norfolk and East Anglia aren't close to Hackney in London.