The thin, dry stuff on the outside of an onion is called the "skin." You can't eat it. The things inside an onion, the parts that you can eat, are called "layers". But the outermost layer, the one closest to the skin, is different from the others. It's harder and tougher. Sometimes, it is so hard that you have to throw it away, just like the skin. At other times, you can trim off the edges, and eat most of it just like the other layers. And sometimes, you can use it in soup, but nothing else. I cook with onions almost every day, and every time I use an onion I need to make a decision about this layer. But I've never had a good name for it. In my part of America, no one ever uses a name for this thing.
But people use onions almost everywhere in the world. I'm sure some languages have names for the thing I'm talking about. You might even have idioms about it. You might use it in special ways. What can you tell me about the outermost layer of onions in your culture?
I found that layers are also called scales or leaves and the skin is also called tunic. Flower bud or a baby flower bud is in the middle and I presume that the first layer under skin or tunic is called thick fleshy leaf.
I didn't find the term in Serbian, but it's probably only a latin term in use.
I usually remove the outer layer or the epidermis so that I can cut it into pieces easily. I don't know and have never heard of any specific name for this outer layer in my language.
I have also noticed people using this upper layer but they cut it into fine pieces.