A constant is a quantity that will not change during operation. How much this amount is has been decided when you compile it, and it will not change no matter how many times you run it.

A variable is a quantity that can be changed during the operation (only, not necessarily).

Function name is the name of the function.

The statement label is just the number in front of the editor or IDE to indicate which line it is, which is convenient for debugging. This is an important concept of 10 years ago, and now it can be thrown into the garbage, because it is no longer needed, and the tools now are very intelligent.

A type definer is a type definer, which literally means.

In addition, among these concepts, only constants and variables are really useful for you to learn programming. Function names are also useful, but actually "function signature" is used more than function name (function signature = function name+parameter list). As for the other two, they can be basically ignored. Statement tags are completely useless, and type descriptors are just a teaching concept. . . You can call it something else. . . It can not be regarded as a professional vocabulary, but as a "type" and "definer"