A multigraph (or pleograph) is a sequence of letters that behaves as a unit and is not the sum of its parts, such as English or French . The term is infrequently used, as the number of letters is usually specified:
Digraph (two letters, as or ) Trigraph (three letters, as or ) Tetragraph (four letters, as German ) Pentagraph (five letters) Hexagraph (six letters) Heptagraph (seven letters)
Combinations longer than tetragraphs are unusual. The German pentagraph has largely been replaced by , remaining only in proper names such as or . Except for doubled trigraphs like German , hexagraphs are found only in Irish vowels, where the outside letters indicate whether the neighboring consonant is "broad" or "slender". However, these sequences are not predictable. The hexagraph , for example, where the and mark the consonants as broad, represents the same sound (approximately the vowel in English write) as the trigraph , and with the same effect on neighboring consonants.
The seven-letter German sequence , used to transliterate Ukrainian , as in for "borscht", is a sequence of a trigraph and a tetragraph rather than a heptagraph. Likewise, the Juu languages have been claimed to have a heptagraph , but this is also a sequence, of and .
Beyond the Latin alphabet, Morse code uses hexagraphs for several punctuation marks, and the dollar sign is a heptagraph, . Longer sequences are considered ligatures, and are transcribed as such in the Latin alphabet.
See also
Unigraph (orthography)