typography, a grapheme is the fundamental unit in written language. Graphemes include alphabetic letters, Chinese characters, numerals, punctuationmarks, and all the individual symbols of any of the world's writing systems.
phonemic orthography, a grapheme corresponds to one phoneme. In spelling systems that are non-phonemicndash such as the spellings used most widely for written Englishndash multiple graphemes may represent a single phoneme. These are called digraphs (two graphemes for a single phoneme) and trigraphs (three graphemes). For example, the word "ship" contains four graphemes ("s", "h", "i", and "p") but only three phonemes, because "sh" is a digraph.
glyphs can represent the same grapheme, meaning they are allographs. For example, the minuscule letter " a" can be seen in two variants, with a hook at the top , and without <ɑ>. Not all glyphs are graphemes in the phonological sense; for example the logogram ampersand("&") represents the Latin word "et" (English ‘and’), which contains two phonemes.
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