A hobbyhorse is a pet topic or personal interest, sometimes to the point of obsession, dates in this sense from the mid-17th century. Its abbreviation, hobby, which means the same thing, dates from the early 19th century. Back in the 1500s, a ‘hobby’ was a small, ambling or pacing horse, but by the early 1600s, a hobbyhorse was a wickerwork or wooden horse used by Morris dancers and then taken up as a toy by children. As a toy, a hobbyhorse was no more than stick with a horse’s head, which children would pretend to ride. Thus, it became a favourite pastime and eventually evolved into the current meaning by the mid-1800s.