Double-byte character set

A double-byte character set (DBCS) is a character encoding in which either all characters (including control characters) are encoded in two bytes, or merely every graphic character not representable by an accompanying single-byte character set (SBCS) is encoded in two bytes (Han characters would generally comprise most of these two-byte characters). A DBCS supports national languages that contain many unique characters or symbols (the maximum number of characters that can be represented with one byte is 256 characters, while two bytes can represent up to 65,536 characters).

Source: Wikipedia — Double-byte character set (CC BY-SA 4.0)