What is truly interspecific?

My understanding is the plumcots/aprium/pluots are true interspecific hybrids…

However, I have read some of the others, like various cultivars called peachcots, pluerry, and nectarcots May not actually be hybrids despite how they are advertised. Does anyone have a list of the “real” ones?

You can read through Dave Wilson nursery interspecific fruits tree by Floyd Yaiger genetics.

http://www.davewilson.com/product-information/category/fruit-trees

Tony