What is the difference between multibyte encoding and Unicode?

Question

C++ / C#

In VS, there is a "Character Set" field in the project settings and some options are listed, for example:

• Use Unicode character set
  
• Use multibyte encoding
  

etc.
As I understood (assumed), a Unicode string is an array of unsigned short int
Then what is a multibyte string? Just an array of more capacious numeric types?

Answer 1

https://msdn.microsoft.com/ru-ru/library/cwe8bzh0.aspx
https://ru.wikipedia.org/wiki/DBCS
Before Unicode, there were also encodings with a character size of more than a byte.

Answer 2

well, if it’s like by analogy with Mysql, then the difference is that the multibyte encoding is an extended unicode (for example, emojis are added)