A grapheme is the smallest semantically distinguishing unit in a written language, analogous to the phonemes of spoken languages. A grapheme may or may not carry meaning by itself, and may or may not correspond to a single phoneme. Graphemes include alphabetic letters, typographic ligatures, Chinese characters, numerical digits, punctuation marks, and other individual symbols of any of the world's writing systems.
The word grapheme is derived from Greek γράφω gráphō ("write"), and the suffix -eme, by analogy with phoneme and other names of emic units. The study of graphemes is called graphemics.
Graphemes are often notated within angle brackets, as ⟨a⟩, ⟨B⟩, etc. This is analogous to the slash notation (/a/, /b/) used for phonemes, and the square bracket notation used for phonetic transcriptions ([a], [b]).
In the same way that the surface forms of phonemes are speech sounds or phones (and different phones representing the same phoneme are called allophones), the surface forms of graphemes are glyphs (sometimes "graphs"), namely concrete written representations of symbols, and different glyphs representing the same grapheme are called allographs. Hence a grapheme can be regarded as an abstraction of a collection of glyphs that are all semantically equivalent.
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