Learn Swedish: Hunden får den dyra behandlingen hos veterinären. - The dog is getting the expensive treatment at the vet's.

The preposition hos specifically means "at the home or workplace of" a person. Because a vet (veterinär) is a person, we use hos to mean "at the vet's clinic". If you were talking about a place rather than a person, like an animal hospital (djursjukhus), you would use på.

Why is it den dyra behandlingen and not just den dyra behandling?

This is a classic example of Swedish "double definiteness." When you put an adjective before a definite noun, you need both the separate word for "the" (den) AND the definite ending attached to the noun itself (-en in behandlingen). The adjective also takes an -a ending (dyra).

Why is the definite form veterinären used after hos?

Just like in English where we say "at the vet's" or "at the doctor's", Swedish uses the definite form (veterinären) with hos to refer to the specific professional the dog is seeing, rather than just any unspecified vet.

Does får always mean "getting" or "receiving"?