A wide character is a 2-byte multilingual character code. Any character in use in modern computing worldwide, including technical symbols and special publishing characters, can be represented according to the Unicode specification as a wide character. A wide character is a computer character datatype that generally has a size greater than the traditional 8-bit character. The increased datatype size allows for the use of larger coded character sets. That means that every encoding standard that uses his characters can grow to a size larger then 8 bits should use wide chars to hold the data of the char (for example UTF-8 or UTF-16)
A wide character refers to the size of the datatype in memory. It does not state how each value in a character set is defined. Those values are instead defined using character sets
There is no guarantee whenever wide char will be effected from endianness or not, because it is just a data type and not an actual encoding implementation. Each operating system use its own encoding standard, For example, UTF-16 little endian is the standard for Windows.
The width of wchar_t is compiler-specific and can be as small as 8 bits. Consequently, programs that need to be portable across any C or C++ compiler should not use wchar_t for storing Unicode text. The wchar_t type is intended for storing compiler-defined wide characters, which may be Unicode characters in some compilers.