When buying a horse what does onvo mean?

"Onvo" is not a standard term used in horse buying or any related field. It's possible you've misheard or misspelled the word.

Here are some terms related to horse buying that might be what you're thinking of:

* "On offer" - This means the horse is available for purchase.

* "Sound" - This refers to the horse's physical health and ability to perform without limitations.

* "Owner" - This is the person who owns the horse.

* "Vet check" - This is a veterinary examination of the horse to assess its health.

Could you please clarify what you mean by "onvo"? Providing more context might help me understand what you're looking for.