[NoPicklez]

It has been defined many times and it's not a core problem.

https://world.openfoodfacts.org/nova https://en.wikipedia.org/wiki/Nova_classification

There doesn't need to be one formal globally recognised definition if you understand the intent of the meaning of the word.

Ketchup, protein powder, infant formula, plant-based meat and banana bread are all considered highly processed. Banana Bread less so if you decided to make it at home using raw ingredients.