If you want the plain-language definitions, they're in the glossary to Access to Therapeutic Products, which I think was provided to you. It's an oversight document.
For example, an adverse reaction in here is stated as the following: “Any undesirable effect of a health product. This can range from a minor effect such as a skin rash to a life-threatening one such as liver damage.” Again, that's not the technical term that's used in the regulations, where it's a “noxious and unintended response”. So it sort of depends on what you want.
The glossary also includes definitions of pharmaceuticals. For example, post-market surveillance is defined as such: “The process of tracking drugs and other therapeutic products, already approved and on the market, to assess signals and safety trends once these products are in use among a wider population.”
That's sort of what you want, right?