I've alway thought backed was a common term in USA. I've heard it since I was a young girl and I am no longer young! Backed, to me, means someone has sat on the horse in a saddle once or twice. Started would be the next step, the horse was backed and ridden about 30 days.
Thanks for the definitions. Interesting to learn something new. Been around horses for over half a century, owned, bred, raised and trained them but had never heard back, backed, backing used in that way.
I'll have to start asking around to see if my riding buddies have heard of it. I doubt that I start using it though cause I would just confuse myself.LOL