A multibyte encoding for text that represents each Unicode character with 1 to 4 bytes, and which is backward-compatible with ASCII. UTF-8 is the predominant form of Unicode in web pages. More technically: (1) The UTF-8 encoding form. (2) The UTF-8 encoding scheme. (3) "UCS Transformation Format 8," defined in Annex D of ISO/IEC 10646:2003, technically equivalent to the definitions in the Unicode Standard.