Abbrev. for 16-bit Unicode Transformation Format. A method of encoding Unicode codepoints using two-byte unsigned integers; either one or two such integers is used depending on the codepoint. Whether the most- or least-significant byte comes first varies between implementations and is generally indicated by a byte-order mark.
http://www.unicode.org/versions/Unicode5.0.0/ch03.pdf Details of UTF-16 encoding from the Unicode (version 5) standard