Lowsurrogate
Lowsurrogate is a 16-bit code unit in UTF-16 Unicode encoding, occupying the range U+DC00 to U+DFFF. It serves as the trailing part of a surrogate pair, used to encode code points outside the Basic Multilingual Plane (U+10000 to U+10FFFF).
A valid surrogate pair consists of a high surrogate (U+D800–U+DBFF) followed by a low surrogate (U+DC00–U+DFFF).
Lowsurrogates are not standalone characters. Unpaired surrogates or misordered pairs constitute invalid sequences in well-formed UTF-16
See also high surrogate, UTF-16, Unicode supplementary planes.