Although I am not a formally trained linguist, I studied linguistics for years on my own (some of my favorite authors include Steven Pinker and John McWhorter). I also cannot think of a term in everyday English that describes such words. That is, they are not examples of portmanteaux, words such as "biopic" (from "biographic picture") or "podcast" (from "iPod" and "broadcast").
In linguistics, there are the terms compounding and blending that describe specific types of word or partial-word combinations. "Blending" seems akin to "portmanteau"--mashing bits and pieces of two words together to form a single word. "Compounding," on the other hand, leaves both words intact when combining them. These can occur in several forms:
noun-noun (e.g., "bonehead" (a special type known as a bahuvrihi compound))
adjective-noun (e.g., "blackberry")
verb-noun (e.g., "whirlpool")
noun-verb (e.g., "sunset")
I am not sure how all this information may help you in your studies, but I, for one, find it fascinating, and exploring etymologies can certainly help you with any GRE®-style vocabulary question. (I call it "word webbing.")
Good luck with your studies.