That is an excellent question!
I don't really have an answer... just an opinion. I think there's a very fine and vague line between 'close contact' and 'jumping' that varies from person to person
. I grew up being told that a close contact saddle was an english saddle you jumped in that didn't have knee rolls (so you could have more and closer contact to the horse), as opposed to an all purpose saddle that has a dressage influence, had knee rolls, and usually a deeper seat. But almost all the close contact saddles these days have knee rolls! I still consider them to be close contact. I consider a 'jumping' saddle to be anything that's suitable for jumping, for example a close contact saddle or an all purpose saddle. Sooo... that's my personal definition. Perhaps other people will disagree.