Words can degenerate in another language, or be incorrectly introduced altogether. For instance, I've heard people call a ceiling lamp a плафон in Russian. In fact, plafonnier is the ceiling lamp in French; plafond is the ceiling itself. :D There are lots of examples of that kind of thing. Sometimes I wish Ukrainian would borrow back more slavic versions of certain words like гостинниця and дворець instead of готель and палац.

What was called шніцель in Soviet times. was also breaded minced meat... Only відбивна (Rus отбивная) was really similar to a Wiener Schnitzel.

Bonus: котлета по-київськи is Chicken Kiev

So my understanding of what "cutlet" means even in English is shaky (as a native English speaker, it's something one comes across in books, but not the kind that have pictures).

Generally I'm finding two definitions, pretty well encapsulated in the American Heritage Dictionary:

1. A thin slice of meat, usually veal or lamb, cut from the leg or ribs.
2. A patty of chopped meat or fish, usually coated with bread crumbs and fried; a flat croquette.

Which of these things correspond to котлета vs. відбивна?

In German there's even a distinction between "Schnitzel" and "Kotelett". A Schnitzel (as I understand) is just a thin slice of meat, while the Kotelett is taken from the rib part of the animal (pig, cow, calf, lamb) and still contains some part of the bone. But it's not the same like pork ribs, it's rather a Schnitzel with a big bone at one side.

I was very surprised when I ordered my first котлет in Russia and got a Frikadelle instead of a Kotelett. :-D