It is believed that word originated from Hackney, Middlesex (now absorbed into London), an area where horses were pastured.
These animals were called "hacks" as a contraction of "hackney",[1] and was originally used to describe an ordinary riding horse, particularly one for hire.
[3] The term suggests an animal of good disposition and calm manner, particularly one suitable for an inexperienced or purely recreational rider.
[citation needed] In some places, organized hacks are held, where a group of riders go out together for a short, relatively easy ride, either on their own horses or on rented animals.
[1] Hunter hack is a class where horses are shown on the flat but also asked to jump a small number of fences, usually two.