I am searching for an inclusive view and typology of electronic and electrical systems, and the design and engineering concepts etc. that underpin them. Is there a widely used vocabulary for electronics and electrical systems, much like the Unified Medical Language System (UMLS) for medicine?
No, not that I'm aware of.
As someone who helped out in a physician's office: I have my doubts about the UMLS thing. I only know ICD, and that's only used to formalize diagnoses. And it is so subjective and formed by the ideas of those standardizing it that it hardly counts as the common language of doctors when describing diagnoses. And that's albeit diagnosis is just a tiny, tiny subfield of human medicine…
Any field has a lot of terms. Medicine and electrical engineering don't really differ in that respect. Also, every field has different ways of looking at things. The way I'll explain how some communications technology works might have not much to do with how the next engineer does it, even if we correctly both describe the same thing. And: with books and articles being written, answers being drafted here, and engineers talking at work, language is always in the flow.
Such a compendium of language is bound to be outdated within very short time, and indeed, the 39 GB (!) of UMLS are far more than just a dictionary. They contain semantic links and description of these, ways to generate field-specific views of the data and many tools to even make that huge dump of data useful.
I have immense respect for that level of effort, and especially in human medicine and biology, it might be extremely important to have a canonical reference for meaning of words. In electrical engineering, that need might just be lower – for all basic things, you can just deliver your mathematical definition alongside your statement. If that definition doesn't match someone else's definition, not really a problem, they can just apply math to figure out whether the statement is relevant to their case. In human biology, you can't just "define" something mathematically. You need to have a list of discrete features that make up anything. Even very fundamental things. What is a "liver"? Does it include the arteries running into it? If yes, how far out? Is that the same in humans as in bats?
So, no, EE doesn't have something like that – you can certainly buy thick books that say "dictionary of electrical engineering" and are essentially something that only students look into, maybe 10 times during their whole studies, and engineers in universities tend to have in the library, catching dust until once every 3 years, someone comes and looks up what an "oscillogram" might have meant in 1950.
There is IEEE Standard 100-2000 - The Authoritative Dictionary of IEEE Standards Terms. The 2000 means that is hasn't been updated in 20 years. It has been withdrawn. The best definitions are those presented in text books along with diagrams and complete explanations of the concepts involved. Many standards contain a glossary of terms that are essential for understanding and applying the standard. Many manufacturers publish handbooks and application guides that contain glossaries. If you look at two or three and find similar definitions, you can have some confidence that there is a consensus on the use of the terms.
If you find a term that is used to describe an "improved" product, but is not well defined or consistently used, that term is likely a "marketing" term. Marketing terms are not engineering terms. They may be useful, but not dependable. The underlying specifications must be carefully studied as applied to each usage.