UCS transformation format
One of a set of standard character encodings, the most widely used of which are UTF-8, UTF-16, and UTF-32. The code tables in ISO 10646 and in the Unicode standard are identical, although the Unicode standard includes additional material.
UTF-8 is the most widely used encoding, at least on Unix systems. Since it does not include any bytes like '\0' or '/' which have a special meaning in filenames and other C library function parameters, and 7-bit ASCII characters have the same encoding under both ASCII and UTF-8, the required changes to existing software are minimised.
Other UTFs: UTF-1 and UTF-7 are not widely used.