Terminology
Historically, the term character has been widely used by industry professionals to refer to an encoded character, often as defined by the programming language or API). Likewise, character set has been widely used to refer to a specific repertoire of characters that have been mapped to specific bit sequences or numerical codes. The term glyph is used to describe a particular visual appearance of a character. Many computer fonts consist of glyphs that are indexed by the numerical code of the corresponding character.
With the advent and widespread acceptance of Unicode and bit-agnostic encoding forms,, a character is increasingly being seen as a unit of information, independent of any particular visual manifestation. The ISO/IEC 10646 (Unicode) International Standard defines character, or abstract character as "a member of a set of elements used for the organisation, control, or representation of data". Unicode's definition supplements this with explanatory notes that encourage the reader to differentiate between characters, graphemes, and glyphs, among other things.
For example, the Hebrew letter aleph ("א") is often used by mathematicians to denote certain kinds of infinity, but it is also used in ordinary Hebrew text. In Unicode, these two uses are considered different characters, and have two different Unicode numerical identifiers ("code points"), though they may be rendered identically. Conversely, the Chinese logogram for water ("水") may have a slightly different appearance in Japanese texts than it does in Chinese texts, and local typefaces may reflect this. But nonetheless in Unicode they are considered the same character, and share the same code point.
The Unicode standard also differentiates between these abstract characters and coded characters or encoded characters that have been paired with numeric codes that facilitate their representation in computers.
Read more about this topic: Character (computing)