A "chillu", or a "chillaksharam" (, "cillakṣaram"), is a special consonant letter that represents a pure consonant independently, without help of a virama. Unlike a consonant represented by an ordinary consonant letter, this consonant is never followed by an inherent vowel. Anusvara and visarga fit this definition but are not usually included. ISCII and Unicode 5.0 treat a "chillu" as a glyph variant of a normal (“base”) consonant letter. In Unicode 5.1 and later, however, "chillu" letters are treated as independent characters, encoded atomically.