A rescue is a dog someone "rescues" from a shelter, kill or no kill or some other unsavory situation. They can be purebred with or without papers, or mutts..any breed because it doesnt make a difference.
In the world of folks who handle , work at vet offices, shelters and breeders..a 'rescue" is a dog who someone acquired by means of a situation upon the dogs circumstances.
Both my pups are purebreds ( Bella however I question but supposedly she is papered, as well as Danny but I dont care)
For example, both are "rescues" because I adopted them not strait from the puppy litter..they were both seniors actually.
Neither have hands ..but they both hold my heart.
I've always wanted pup..African Borebol or Cane Corso pup. Both are serious pups needing serious training, time n energy. Having to work as much as I still do doesnt allow me to commit to that endeavor as it should ..so..the older rescue pups are a good fit for us both.
Over the years, I've noticed mutts are less needy as far as vet services go. They are hardy and tend to get the best of what breeds they embody.
The purebreds I have n have had tend to be the problem child. Overbreeding has taken its tool on many purebreds. Danny Dog seems to not be affected but..they are not a popular breed in the west.
Just my observations...